Death's Mane Jellyfish Species in Cairne | World Anvil

Death's Mane Jellyfish

Basic Information


A staggeringly huge creature that measures on average two hundred feet or more from top to the end of its tentacles. These creatures are nearly invisible in the water due to their translucent nature unless they have fed recently, which will show a small hint of color as whatever they have caught and devoured is slowly worked through their digestive tract. Their tentacles are a huge mass of thin tendrils, each carrying a deadly venom and covered with adherent chemical that makes them difficult to remove.

Genetics and Reproduction

The Death's Mane reproduces asexually through strobilation, the process of forming segmented polyps. A fertilized egg is dropped forming a planula which attaches to the ocean floor. From there it forms the polyp which grows until it reaches enough development to be released as an ephyra, an immature jellyfish. This eventually grows to maturity and becomes the adult Death's Mane.

Growth Rate & Stages

While these creatures are very hard to study, the few that have been captured for observation have remained in polyp form for many years. It seems as though they have the ability to wait until they sense conditions are optimal for the release of the ephyra. The ephyra matures over the course of approximately a year, but the lifespan beyond that remains a mystery. There is no known limit to how long one of these creatures can survive.

Ecology and Habitats

While they seem to prefer cold water, these creatures adapt quickly to new aquatic environments. As long as there is enough food to sustain them, they will thrive.

Dietary Needs and Habits

The Death's Mane utilizes food primarily for growth, and can actually go many days without eating. If it goes too long without feeding, it will begin to diminish in size.

Additional Information

Geographic Origin and Distribution

The Death's Mane seem to remain primarily in colder, deeper water, and a large community has been reported drifting through the realm known as Nether's Deep, but they have been known to migrate from time to time, causing a great deal of damage to the local populations of fish and often frightening coastal communities that do not know what they are.

Average Intelligence


Perception and Sensory Capabilities

Sensory perception is achieved by use of small, finger-like protrusions that hang from the outer edge of the bell that makes up its bulk. These hyper-sensitive tendrils use the movement of the water and the push of gravity itself to navigate up and down and have some sense of current. There is also a very small point located in the center of the bell that is mildly photosensitive, allowing it to maintain a sense of light and dark as well.
Scientific Name
Lion's Mane Jellyfish
Average Weight
250 pounds for an average adult.
Average Length
200 Feet from top to the end of tentacles for an average adult.
Body Tint, Colouring and Marking
These creatures are translucent until they have fed, at which time a slight reddish hue can be seen radiating from whatever point their food is within them, a result of the nutrients being slowly pulled from the body of their prey.
Geographic Distribution

Cover image: Deaths head by Midjourney


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