Larvac
The Larvac is an enemy in the Keen 4 mod Atroxian Realm by Gridlock.
Larvacs are blob-like creatures which are native to planet Krisle. Apparently the winged bat-like creature known as the Larvbat begins it's life as a Larvac, crawling along the ground inside a globular blue cocoon. A large green spot adorns it's side (possibly an eye), and on top of the grotesque grub is a round toothy mouth. As the Larvac crawls around it will spit, retching forth large green globs of slimy acid into the air. Larvacs can be primarily found in the Larvae Lagoon which is their native habitat, but a few can also be encountered in the Crystallite Caverns.
The in-game help text states - Thriving in dark underground areas, these caccooned larvbats experience bad acid reflux. Watch out for their corrosive spit!
The Larvac is a Poison Slug replacement.