The Cucumber Slug was a species of slug native to Atlantis. While approximately the size and shape of a cucumber, its vivid, iridescent shade of green seemed almost unnatural. As was typical of the breed, it had eyestalks and left a trail of slime as wide as a man's thumb.
John James Audubon spotted one on a redwood sapling during his 1843 excursion to Atlantis. While neither a bird nor a viviparous quadruped, Audubon elected to stop and sketch it since the creature was a curiosity little known to science.
The Atlantean Museum in Hanover, Atlantis had a display of a cucumber slug made of plaster of Paris on the side of a redwood with a mucilage trail. Athelstan Helms visited the museum when he came to Atlantis in the mid-1880s but was disappointed that the display was artificial rather than a live slug.