Monster Monday: Giant Sea Slug, Stinging Mollusk of the Reefs

Today's Monster Monday is the giant sea slug or giant nudibranch. These colorful, poisonous, acid-spitting creatures lurk in reefs or the open sea, feeding on coral and giant jellyfish, occasionally swarming shipwrecks or attacking castaways.

Clockwise from top left: Nembrotha aurea, Berghia coerulescens, Glaucus atlanticus (sea swallow or blue dragon), and Hexabranchus sanguineus (Spanish dancer). Via Wikimedia.

Sea slugs are carnivorous shell-less mollusks, far more varied and colorful than the garden slugs with which we are all familiar. Some crawl along the seafloor, others - like Glaucus atlanticus - cling to the surface tension of the water, and still others - like the Spanish dancer - can ripple and undulate through the water. In nature, sea slugs become poisonous by absorbing the stinging cells of jellyfish and hydrozoans that they eat, thus turning their prey's defenses into their own.

Giant sea slugs, as statted up below, combine elements from many different real species of sea slug, except instead of being tiny they are ten feet long and capable of feeding on giant jellyfish and even humans.

The following text in gold is available as Open Game Content under the OGL. Open Game Content is ©2018 Jonah Bomgaars.

Monster Monday: Sea Bear - The Orca-Hunting Ursid

Today's Monster Monday is the sea bear, a massive grizzly bear adapted to an aquatic lifestyle, which uses its bulk, strength, and cunning to hunt salmon, seals, and even the mighty orca. The sight of their distinctive three-dorsal-finned back rearing out of the water is a sign to whales and fishermen alike to scatter, as the mighty sea bear is on the hunt.

This creature is based on the chaan xúujaay from the mythology of the Haida people of Haida Gwaii off the coast of British Colombia. The sea grizzly bear appears as a motif in Haida artwork, combining elements of bear and orca (see this hat and its description at the Seattle Art Museum).

The following text in gold is available as Open Game Content under the OGL. Open Game Content is ©2018 Jonah Bomgaars.

Monster Monday: Chordopod, Bony Tentacle Beast

Today's Monster Monday is the chordopod, an undead monstrosity that takes the rough form of an octopus or spider made of bones. At its center is a large skull-shaped head formed from twisted and distorted bones, while its many tentacles or legs are long spinal columns which whip and curl and crawl. This twisted undead abomination is the result of a great outpouring of negative energy in places such as mass graves, battlefields, and shipwrecks where the remains of many individuals are left to mingle and decay anonymously.

With the ability to burrow, climb, and swim, these nimble monstrosities are all-terrain foes (I guess you're safe in the sky, unless one of them grabs onto the hull of your airship as you are taking off). I can see them bursting out of the desert sand just as easily as I can see them bursting out of the storm-wracked ocean or bursting through the troubled earth of a bloody battlefield. I guess I just picture them bursting through things.

Also in the stat-block below, a diseased variant that rises from the mass graves of plague victims and stalks through the streets of disease-wracked cities or the pestilential countryside, spreading filth and rot in their wake.

The following text in gold is available as Open Game Content under the OGL. Open Game Content is ©2018 Jonah Bomgaars.

Monster Monday: Ammonites - Spiral-Shelled Cephalopods of Prehistoric Seas

Today's Monster Monday is the ammonite, a hard-shelled nautilus-like creature that floated through the prehistoric seas for some 350 million years before being wiped out in the same extinction that ended the age of the dinosaurs.

Ammonites typically had a spiral shell made up of successively smaller chambers that they could flood with gas or water to control their buoyancy. The animal itself was a cephalopod, probably ten-armed, which protruded from the end of the shell. Some ammonites may have been able to withdraw into their shells like a modern nautilus or a snail. Some may have had ink they could release in a cloud like modern squid and octopuses. But when we are talking about ammonites, we are talking about thousands of species across hundreds of millions of years - there was room for plenty of variation. Some - like the nostoceratidae - had irregularly unwound shells and probably floated through the sea like plankton or jellyfish. Some just crawled along the sea floor. Most ammonites were small, with shell spirals reaching no larger than 9 inches in diameter. But the two types of ammonites we will be looking at today were big.

photo by Ghedoghedo, via Wikimedia

Titanites giganteus - Natural History Museum, London

Titanites giganteus did not let the ocean currents decide where it would go, as if it were some kind of overgrown plankton. No, titanites was a swift hunter, jetting through the ocean in search of prey it could wrap its probing tentacles around and gnaw with its sharp beak. Their shells reached 2-3 feet in diameter, much larger than the typical ammonite of its day. But even the bigly named titanites giganteus was dwarfed by:

photo via Wikimedia

German zoologist Hermann Landois sitting next to his fossil of Parapuzosia seppenradensis,
with a wire frame showing the projected size if the specimen were complete. 

Parapuzosia seppenradensis may be a mouthful of a name, but you would be hard pressed to find a predator capable of making this ammonite into a mouthful. The 5.9 foot diameter fossil seen above is broken - with its intact living chamber, estimates put this specimen at 8.4 to 11 feet in diameter, making it by far the largest ammonite species. In life, the creature may have weighed 3,200 pounds, fully half of which comes from its massive shell. If parapuzosia was a hunter like titanites was, it must have been an impressive and terrifying sight to behold.

The following text in gold is available as Open Game Content under the OGL. Open Game Content is ©2018 Jonah Bomgaars.