Rodrigo B. Salvador1, Natan C. Pedro2, Mark A. Carnall3
1Zoology Unit, Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland.
2Museu de Zoologia da Universidade de São Paulo, São Paulo, SP, Brazil.
3Oxford University Museum of Natural History, Oxford, UK.
Emails: salvador.rodrigo.b (at) gmail (dot) com; natan07 (at) alumni.usp (dot) br; mark.carnall (at) oum.ox.ac (dot) uk
In our plane of existence, molluscs are the second most diverse animal phylum in sheer number of species, losing only to arthropods. They are, however, perhaps the most diverse animal groups in body plans and shapes. The better-known molluscan groups include forms as disparate as snails and slugs (class Gastropoda), octopuses and squids (class Cephalopoda), and oysters and mussels (class Bivalvia). The lesser-known molluscs go from the worm-like aplacophorans to the armadillo-like chitons and the fang-shaped tusk shells. Also, molluscs come in all sizes, from species smaller than 1 mm all the way to the largest invertebrate alive, the giant squid that can reach over 15 m and is the origin of the legendary Kraken (Salvador & Tomotani, 2014).
As arcane specialists on Mollusca and eternal inhabitants of museum galleries and catacombs, we are constantly pondering the existence of molluscan life (intelligent or otherwise) on planes other than our own. Thus, we have discussed squid kids, pixel molluscs, and many others. One of us (Carnall, 2018) has even explored cephalopod diversity across the multiverse of Magic: The Gathering (MTG).
Since then, the MTG’s multiverse has witnessed an explosion of molluscan diversity, notably in the cephalopod and gastropod fronts. The kinship of disparate molluscan classes has even been recognised across the multiverse, as seen in the flavour text of Nightwhorl Hermit, which brings bivalves and snails together: “He etches his secrets onto the shimmering shells of mussels, saving them to share with the Great Snail”. To us, that sounded as a call to arms to ̶s̶p̶e̶n̶d̶ ̶m̶o̶n̶e̶y̶ ̶o̶n̶ ̶c̶a̶r̶d̶s̶ study all these new life forms.
SLUGS AND SNAILS
Perhaps the largest increase in molluscan diversity in MTG took place among the terrestrial gastropods, with a notable contribution from the Bloomburrow set of 2024. Of all the peoples of the Bloomburrow plane, the ratfolk have achieved the pinnacle of enlightenment, with a culture that revolves around gastropods, including worshipping a being known as The Great Snail. Such advanced sensibilities have only one parallel in our plane’s history: the rise of Lord Helix during the Twitch Plays Pokémon event – though the Cult of the Helix involved a fossil cephalopod (Salvador, 2014).
Snails
The legendary rat warlock Wick, the Whorled Mind grew up in the village of Conch and developed a psychic bond with his companion, the sapient snail Grotgyre – a.k.a. The Great Snail or God-Snail. He found enlightenment with the snails (who doesn’t, right?) and roamed the world spreading the slimy Word and gathering followers (Johnson, 2024), such as the Thought Shucker and Lightshell Duo. Wick is seen with several snails in his card’s art, part of which are similar to some of our plane’s land snails but with a few oddballs that have rather unusual shell shapes. That is perhaps an indication that the snails of the multiverse managed to occupy more of the morphospace available to beings with coiled shells (Raup & Michelson, 1965; Raup, 1966).
It turns out, however, that the Great Snail was actually being controlled by a worm-like parasite. That goes to show that mortals should not put too much trust in a god, as already remarked by our plane’s mythologies. In any event, the worm in question is probably similar to the Leucochloridium flatworms from Eurasia that infect exclusively members of the snail family Succineidae, known as amber snails (Ataev et al., 2016; Nakao et al., 2019). The parasitic flatworm manipulates the snail’s behaviour, making it crawl towards places where it is more conspicuous to predators, namely birds, which are the definitive host of the parasite. Clearly, this Bloomburrow parasite can also infect other types of snails besides amber snails, as seen by the tell-tale bulging and striped tentacles of the Snail creature token (Fig. 1).

And speaking of parasites, the Skullcap Snail, from Ixalan, is infested by fungi, like something out of The Last of Us. Even so, we do not have good data on whether this is a parasitic, commensalistic, or mutualistic relationship between the fungus and the snail. In any event, the Skullcap Snail looks more like a slug that rented a skull for a house rather than a proper snail.
The rat spellcaster featured in Mind Spiral is shown with an odd-looking snail shell. That shell is exactly like a fossilised internal mould of a shell – that is, during the fossilisation process, the actual shell sometimes dissolves away, leaving only the mineralised sediment that had filled it up (you can find some examples in Salvador et al., 2018). Finally, let’s just pretend that the chimeric caterpillar-dog-with-ant-like-antennae-and-gastropod-shell known as the Dogsnail Engine doesn’t exist, alright?
Slugs
While the cards above contain all the terrestrial snails we could find around the multiverse, there are plenty of slugs in MTG, contrary to our plane, where snails are much more diverse than slugs. While snails and slugs are perceived as slow creatures, they can be quite active – just ask anyone trying to grow strawberries in their backyard. MTG is thus not free from cultural perceptions, with an Enchantment named Sluggishness. However, only the English language card is offensive; it has more appropriate names in other languages, such as Trägheit in German.
Let us start with the basics. The Slug creature token is overall reminiscent of the members of the Arionidae family found in our home plane. Still, all the teeth positioned around its mouth are completely alien. Actual gastropods have a structure called a ‘radula’ in their mouth, which is like a tongue with dozens of rows of tiny teeth that they use to scrape off their food. Thus, they ingest small morsels of food at a time and are not able to consume an entire skull or creature, as shown in the token’s art. Some marine predatory gastropods, like the cone snails, however, have a radula adapted to hunting fast-moving prey and can ingest entire prey, including fish (Duda et al., 2001).
A similar weird mouth-and-teeth combination can be seen in the Catacomb Slug (from Ravnica), which has way too many tentacles on its head and looks like a cross between a sea hare (a type of marine slug belonging to the family Aplysiidae) and a sea cucumber (part of the echinoderm phylum). Terrestrial slugs (as well as the vast majority of land snails) have only two pairs of tentacles: the topmost pair are eyestalks, with the eyes positioned on their tip; the bottom pair is responsible for the chemical and tactile senses (Chase, 2001).
A good example of the two tentacle pairs is the oldie-but-goodie Giant Slug, from a time when the multiverse had not yet suffered from power creep, and the Rocket-Powered Turbo Slug, arguably one of the greatest cards in MTG. Gluttonous Slug also has two pairs of tentacles, but the second pair is positioned in-between the first one, not to mention it also bears tiny eyes. Weirdly enough, Gluttonous Slug has some leg-like appendages, which give it a rather caterpillar-ish look. The Thermopod, from Dominaria, also look like a cross with a caterpillar because of its three pairs of leg-like appendages and the very arthropod-like mandible. Also, the Molder Slug from Mirrodin has an insect-like or crustacean-like armour plating on its rear end. Still, its armour also bears some passing resemblance to the multiple calcareous plates of chitons, members of the class Polyplacophora and also molluscs.
Slugs typically have their breathing pore (called ‘pneumostome’) on the right side of their bodies, which brings air to their lung. The Spitting Slug from Dominaria, however, has the pneumostome on its left side (Fig. 2). This mirrored anatomy (Schilthuizen & Haase, 2010) indicates that the illustrated slug is a sinistral, or left-handed, specimen – maybe the whole species is made up of sinistral animals! As implied by its name, this slug spits a substance which looks like mucus, which is something no gastropod can do (rather, they produce and secrete mucus through their skin).

Last but not least, we arrive at Toxrill, the Corrosive, the legendary slug horror from Innistrad. Overall, if it were a Pokémon, one could say it evolves from the Morkrut Necropod (also from Innistrad) when it reaches a high enough level. They share a similar body plan, reminiscent of a deflated sea hare that has been taken out of the sea (Fig. 3), have way too many tentacles and a toothed mouth. But, well, we suppose that’s what makes it a slug horror. Curiously, the baby slugs shown around Toxrill have only three pairs of tentacles, implying that extra pairs appear during development. Like all slugs and snails, Toxrill can continuously produce mucus, which is reflected in game terms as slime counters.

SEA SNAILS & SEA SLUGS
Terrestrial gastropods make up about one-third of all gastropod species on our home plane. Except for a few hundred freshwater species, it is in the marine environment that the group shows its highest diversity (Rosenberg, 2014). This remarkable marine diversity is reflected in a wide range of forms, ecological strategies, and evolutionary adaptations. In contrast, marine fauna is not that well explored in MTG, particularly considering it is largely restricted to one out of the five mana colours.
There is one sea snail in MTG: Gary, the Snail (from SpongeBob SquarePants). However, Gary is just a different incarnation of the card Toxrill, the Corrosive, which is a terrestrial slug horror.
Sea slugs have not been particularly lucky either, being present only in the comedy set Mystery Booster. The critters in the card Gunk Slug seem to have been inspired by nudibranchs, such as members of the Chromodorididae family (Fig. 4), which are typically colourful animals with stripes that mark their dorsal region – too bad the card is in black and white!

BIVALVES
On our plane, bivalves are the second most diverse group of molluscs by number of species; however, it seems they may not be as common or perhaps as well studied across the multiverse. There’s evidence of bivalve use in commerce and culture. A Seashell Cameo on a scallop makes for a source of mana in a pinch, and the flavour text from Nightwhorl Hermit and Shore Up indicates that mussels are known well enough to be used as votives and have found their way into vernacular expressions.
Giant Oyster resembles the giant clams, Tridacnidae, of our world (Fig. 5) and also occasionally traps hapless animals within their shells as recorded in mythology, museums, medicine (Marina & Popa, 2020) and media (Martin-Pavitt, 2022).

However, the most evidence of bivalve life from the multiverse comes from one of the two molluscan humanoid creatures (see Cephalids, below), the enigmatic and seemingly haphazard clamfolk. Clamfolk are anthropoid creatures with scrawny arms and legs with a head that resembles, well, a clam. They are the sworn enemies of the anthropoid lobster-like Homarids (McDermott et al., 1998). Not much is known about them, but a well-known song indicates there is at least one clamfolk settlement and music culture:
The Clams down in Clamville
All scootered and skittled
“The three is no more”
The Clam fiddler fiddled
– Flavour text from Clam-I-Am card.
Clam Session and Clam-I-Am indicate that the clamfolk like good music. However, they do wage war and occasionally end up shelling neutral parties, for which they attempt to make good by issuing Clambassadors with reparations. There’s just one clamfolk legend recorded in the histories of the multiverses, and that is Alexander Clamilton, the clamfolk advisor rebel fond of wordplay and duelling rivals.
CEPHALOPODS
Since the previous review of cephalopods of the multiverse (Carnall, 2018), there has been an explosion of newly discovered cephalopods across the multiverse and one major taxonomic change. In 2018 it was just about possible to construct a decent ‘tribal’ octopus deck with a splash of other cephalopod creatures and spells for flavour (in MTG parlance, tribal decks are decks that benefit from running creatures of the same type and in legacy formats can be bolstered by artifacts like Herald’s Horn, Vanquisher’s Banner and Metallic Mimic). Now it is more than possible to create cephalopod-themed decks for formats like Commander, which restricts the number of copies of cards which can be used and have larger deck sizes.
From the monster-dominated plane of Ikoria comes the Sea-Dasher Octopus with the ability to mutate and merge with other creatures and share their abilities. The wonderfully named bioluminescent Octoprophet is a strictly better Giant Octopus with the same power, toughness and casting cost but with scrying power. From the waters of the Ravnica plane, we have the Mesmerizing Benthid, which creates paralysing illusions upon being summoned. Also from Ravnica, it seems the biomancers of the Simic Combine have been particularly inspired by octopus adaptations in their creations of shark-octopus-lizard Unruly Krasis, or, if you prefer your hybrids with more claws, the shark-octopus-crab Sharktocrab has you covered. Rounding off the hybrid/mutant/fusions are disguise artist octopus-fish Bubble Smuggler and robot-glove-octopus device Acquisition Octopus.
There are a number of new cephalopod creatures of such ability and renown that they are known as legends (legendary creatures in MTG have specific rules). From the plane of Muraganda, one of the three planes that is host to the plane-spanning, death-defying Ghirapur Grand Prix, is the legendary Caelorna, Coral Tyrant, an island-sized octopus that eats leylines for breakfast. Proving that octopuses on some planes are also known for their smarts is the elemental Octavia, Living Thesis, the product of one of Strixhaven University’s finest minds. The latest legend to be discovered is one that spans not only planes but franchises: Ultros, Obnoxious Octopus appears in over twenty games in the Final Fantasy series of video games, as well as Dragon Quest and Kingdom Hearts, and now joins the MTG multiverse thanks to a popular crossover set.
There’s also been an update to the classification, from an arcane taxonomy point of view anyway, so update your codices, spell books and living tomes accordingly. Cephalids, MTG’s humanoid cephalopod race, are now, thanks to a rules change, octopus creatures, which now means they won’t be washed away by Whelming Wave and can be summoned up by Kenessos, Priest of Thassa. Cephalids are generally depicted as cruel, conniving and crafty, as indicated by card names, art and flavour text such as Callous Oppressor, Cephalid Aristocrat, Cephalid Looter, Cephalid Snitch and Cephalid Vandal. Cephalids play an important role in MTG’s ongoing plane-spanning mythology. Aboshan, Cephalid Emperor once ruled the cephalid Mer Empire of the plane Dominaria’s oceans but fell foul of the temptations of legendary MacGuffin, the Mirari, as told in the MTG novel Odyssey (Moore, 2001). Most recently, after a twenty-year absence, cephalids are back in MTG, putting their cunning and conspiring to good use on the mean streets of New Capenna on the plane Capenna. In a city where demon-led crime families vie for dominance, cephalids have found employ as goons for hire (Backstreet Bruiser), spies (Cephalid Facetaker) and information dealers (Psychic Pickpocket), among others.
Rounding off the cephalopod mollusc new discoveries across the planes, and it’s not just octopuses which have seen some love from the designers of MTG. There’s one new nautilus, the conchokleptic Hermitic Nautilus, which wears the shell of the devoured previous owner (that looks vaguely familiar to another MTG cephalopod). There’s tantalising evidence of a fossil record of nautiloids from the plane of Theros, Pull from the Deep, depicts a rather fortuitously preserved fossil (or possible carving) of a nautiloid shell in section, perfectly showing the central siphuncle and nautiloid septa (Fig. 6). There are just two new squid: Skyclave Squid, the multiverse’s first cuttlefish, perhaps; and the rather dapper and dastardly Squidnapper from Mystery Booster, one of MTG’s occasional comedy sets.

Several other spells and creatures create, summon and otherwise combo with octopuses. Take care at the Astroquarium lest an octopus escape. Octomancers are frog druids who, well, mancy octopuses. You’ll need to study hard for transformation lessons at Strixhaven to polymorph an octopus or frog (or should that be crab?) with Mercurial Transformation. Origami fans might want to practice for Octo Opus the next time the circus is in town. Summon: Leviathan will wash away everything but octopuses, krakens, merfolk, serpents and leviathans and if you spend some time levelling up with rod and tackle and you’ll be fishing up octopuses in no time with a bit of Fisher’s Talent. Lastly, various legends from the multiverse will bolster your suckered and tentacled troops: Kenessos, Priest of Thassa can help you get more octopuses onto the battlefield; planeswalker Kiora has two new aspects Kiora, the Rising Tide and Kiora, Sovereign of the Deep; and Krothos, Lord of the Deep can double your cephalopod forces with every attack.
CONCLUSION
We hope we have covered all the main molluscs from MTG, but feel free to let us know about further instances of mollusc-related stuff and “cameos”. Echoing the ending remarks of Carnall (2018), we see some biological similarities in the molluscs of the multiverse, together with biologically questionable, implausible or outright impossible stuff – all in the name of making a fun game. There are still plenty of molluscs in our home plane to draw inspiration from, particularly the fossil ones, so we look forward to seeing more of them in MTG in the future.
REFERENCES
Ataev, G.L.; Zhukova, A.A.; Tokmakova, A.S.; Prokhorova, E.E. (2016) Multiple infection of amber Succinea putris snails with sporocysts of Leucochloridium spp. (Trematoda). Parasitology Research 115: 3203–3208.
Carnall, M.A. (2018) Cephalopods of the Multiverse. Journal of Geek Studies 5(2): 60–68.
Chase, R. (2001) Sensory organs and the nervous system. In: Barker, G.M. (Eds) The Biology of Terrestrial Molluscs. CABI, Wallingford. Pp. 179–211.
Duda, T.J.; Kohn, A.J.; Palumbi, S.R. (2001) Origins of diverse feeding ecologies within Conus, a genus of venomous marine gastropods. Biological Journal of the Linnean Society 73: 391–409.
Johnson, N.L. (2024) The legends of Bloomburrow. Magic: The Gathering. Available from: https://magic.wizards.com/en/news/feature/the-legends-of-bloomburrow
Marina, V. & Popa, F. (2020) An unusual case of leg wound made by a Sea Shell (Scapharca inaequivalis). International Journal of Surgery Case Reports 67: 127–129.
Martin-Pavitt, R. (2022) Bird with beak stuck inside oyster shell rescued by group of friends. Independent. Available from: https://www.independent.co.uk/tv/lifestyle/essex-bird-oyster-shell-rescued-b2019822.html (Date of access: 09/Jul/2025).
McDermott, W.; Rosewater, M.; McGough, S. (1998) Hatch your own plot. The Duelist 29: 63.
Moore, V. (2001) Odyssey. WotC, UK.
Nakao, M.; Sasaki, M.; Waki, T.; et al. (2019) Distribution records of three species of Leucochloridium (Trematoda: Leucochloridiidae) in Japan, with comments on their microtaxonomy and ecology. Parasitology International 72: 101936.
Raup, D.M. & Michelson, A. (1965) Theoretical morphology of the coiled shell. Science 147: 1294–1295.
Raup, D.M. (1966) Geometric analysis of shell coiling: general problems. Journal of Paleontology 40: 1178–1190.
Rosenberg, G. (2014) A new critical estimate of named species-level diversity of the recent Mollusca. American Malacological Bulletin 32: 308–322.
Salvador, R.B. (2014) Praise Helix! Journal of Geek Studies 1(1-2): 9–12.
Salvador, R.B. & Tomotani, B.M. (2014) The Kraken: when myth encounters science. História, Ciências, Saúde – Manguinhos 21: 971–994.
Salvador, R.B.; Adaci, A.; Benyoucef, M. (2018) Terrestrial Gastropoda from the Pleistocene of Beni Saf, NW Algeria. Annales de Paléontologie 104: 291–300.
Schilthuizen, M. & Haase, M. (2010) Disentangling true shape differences and experimenter bias: are dextral and sinistral snail shells exact mirror images? Journal of Zoology 282: 191–200.
Acknowledgements
We are very grateful to Ilkka H. J. Kivistö for helping to compile the list of slug/snail cards; this venture would have been much more difficult (and probably incomplete!) without his help.
About the authors
Dr Rodrigo B. Salvador is the curator of (non-insect) invertebrates at the Finnish Museum of Natural History, and his research speciality is land and freshwater snails. He played a lot of MTG during his teenage years and early 20s, spending more money on cards than he’d like to acknowledge. He hasn’t played since the Lorwyn block was released, but he keeps a watchful eye on what’s happening in the multiverse while resisting the temptation of buying more cards.
MSc. Natan C. Pedro is a PhD student at the Museum of Zoology of the University of São Paulo (USP), where he focuses on the study of carnivorous marine snails. An MTG player for over 15 years, he found in the game’s multiverse a passion as intense as the one he feels for Biology. Fascinated by diversity, whether in the oceans or on the cards, he has amassed a number of decks that defy any kind of mana control… or available space at home.
Mark Carnall is the collections manager of non-entomological invertebrates and human remains at the Oxford University Museum of Natural History with an inordinate fondness for cephalopods. Mark has spent years trying to build the perfect strictly cephalopod tribal deck and asks that you please wait until turn five because blue creatures are expensive okay but after that you’re in trouble.