I was recently at a jellyfish spawning lab, where I discovered the jellies I’d swum through during my SCUBA lessons were Moon Jellyfish. This led me down a rabbit hole of thought – the largest jellyfish in the world wash up occasionally on the shores of Cornwall. Could a magus take one as a familiar? What other uses could we find for the lion’s mane jellyfish?
The largest observed lion’s mane jellyfish had a bell 2.3 meters wide, and tentacles 37 meters long, although most are smaller, with bells in the 50 cm range. The further north you are, the larger they tend to be. The largest have the darkest colouration, a sort of purple, while smaller ones are red, blue, orange or transparent. The link of purple and lions suggest Rego vis.
Statistically, a jellyfish is tricky to model. Unlike a squid, you don’t want to work out an attack for each tentacle. The way around that is to treat the tentacles like an environmental effect. We’ve done this for swarms before, and for the body mass of elementals. I’d suggest the same for jellyfish.
The lion’s mane lacks useful propulsive capability. It just bobs with its bell parallel to the surface, depending on currents to travel any great distance. This reminds me of the early Criamon who saw themselves as the followers of a universal principle of the inevitable, and their Prima, who floated about the place, never touching the ground, using magical powers that had become second nature to her. Could you make a familiar that, similarly, just sort of floats in the air, or even in a column of water in your covenant?
If you take something as amorphous as a jellyfish as a familiar, does this change the physical structure of the jellyfish markedly? We know that the sigil of the magus will transition across, and that pets come to look like their owners. Is this one way that your magus might get a floating brain as a familiar? After all, once you attach the silver chord, it gains intelligence. Presumably it stores that intelligence in an organ of some type?
Barrel Jellyfish
A related, species, the barrel jellyfish, is also found in Cornish waters. Their maximum size is smaller than the lion’s mane, about six feet long. They weigh about 70 pounds, so they are arguably Size 0 or -1. Lion’s mane jellyfish tend to be smaller the further south you go, so the barrel jellyfish near Cornwall are often larger.
This species has a wider variety of colours than the lion’s mane, although deep blue is the most common. Instead of the great net of stinging tentacles found on the lion’s mane, it has four feeding arms. This allows it to be written up as a variant of the water elements or squid we’ve seen before. It doesn’t have stingers, but it does have frills that give it a distinctive look.
Barrel jellyfish are capable of swimming at a constant rate of about 5 centimetres per second, which they mostly use to resist tidal flows, so they aren’t swept out into the open ocean. This has only recently been discovered, but assuming they do it in Mythic Europe, that’s about 18 kilometres per hour, extrapolated out to an extraordinary degree. That speed is comfortably placed between human jogging speed and distance running speed, so if a barrel jellyfish were adapted to life on land by the familiar bond, it could keep up with a travelling magus.
Plot hooks
Barrel jellyfish gather in huge groups, which makes it suitable for vis harvesting.
It’s usual to bind an animal which has abilities you want to develop yourself. Many combat magi have eagle familiars because it gives them extended Sight Range, for example. There’s one species of jellyfish that is effectively immortal: it can repeatedly transform into its adolescent state, age to maturity, and then cycle back. These were not known in medieval Europe, but make a really interesting treasure for a high fantasy game. They don’t necessarily overpower the game, because the process of deaging would not prevent Twilight points accruing.
This species of jellyfish was the cause of death in one of the Sherlock Holmes stories. You might reskin that story, and add a Guernicus magus, trying to discover if a character had killed a romantic rival. Although the lion’s mane is poisonous, it generally doesn;t kill humans: it hurts, but only ends life in those with low Stamina, possibly due to Decrepitude.
Bjornaer magi often become enormous versions of their Heartbeats, rather than falling into Twilight. I’ve been trying to find a likely candidate for an Irish cryptid called the Whale Eater. This isn’t it, but it does make me wonder if there’s a Bjornaer magus who has headed to the cold north, to become a lion’s mane of tremendous size.
Characters based on the Scilly Islands are possibly seeking a strange little sept of Criamon magi. Ccould they have had jellyfish familiars? Could one of these familiars have survived to provide clues as to where the magi have gone? A jellyfish is up to 95% water. What if a magical spirit in the form of jellyfish was filled to 95% with the material that makes up the current of vim that allows magic to be performed in Mythic Europe? What if, further, the magi had taken that ability upon themselves in an attempt to reach rapidly into the Hall of Heroes or into Twilight? Could characters find the notes for such a bizarre practice. What happens if they follow it themselves? It might lead to rapid advancement in one of the Criamon paths, but your saga may vary.
Games From Folktales 