The lion's mane jellyfish (Cyanea capillata)

The lion's mane jellyfish appears in the Sherlock Holmes short story "The Adventure of the Lion's Mane" published in The Case-Book of Sherlock Holmes. Holmes discovers at the end of the story that the true killer of a professor who died shortly after going swimming (shouting "the lion's mane" before he succumbed) was actually this jellyfish. Suspicion was originally laid upon the professor's rival in love, until the latter was similarly attacked (he survived, although badly stung). In the context of the story, it is only because the school professor has a weak heart that he succumbs, as is confirmed by the survival of the second victim.

A photograph widely distributed on the internet appears to show an anomalously large lion's mane dwarfing a nearby diver by several times. The photo was subsequently shown to be a hoax.[18]

On the popular television program QI, the show claimed that the longest animal in the world was the lion's mane jellyfish. This was later corrected – in 1864, a bootlace worm (Lineus longissimus) was found washed up on the coast of Fife, Great Britain, that was 55 m (180 feet) long. (This claim is disputed because bootlace worms can easily stretch to several times their natural length, it is possible the worm did not actually grow to be that length