[2] E. atroviridis slugs live up to three meters deep, and are generally dark green in skin colour with small, black spots all around the body.

[4] E. atroviridis and Elysia marginata are notable for possessing the ability to completely autotomize their bodies and grow them back within 20 days.

[5][6] Being a member of the superorder Sacoglossa, E. atroviridis is capable of kleptoplasty,[7] which is the process of taking chloroplasts from digested algae and using them for photosynthesis.

The bodies never regrew the head, and responded to tactile stimuli, but eventually stopped and grew pale, presumably from losing chloroplasts.

[5] Other theories for the function of the autotomy include escaping algae the slugs are tangled in and removing accumulated toxic chemicals.