A Vulcan sandworm
The Vulcan sandworm was a type of animal native to the planet Vulcan.
Doctor Phlox kept Vulcan sandworms as food for some of his pets. From time to time however, he would eat a sandworm himself. (ENT: "Dear Doctor")
In 2153, when Phlox was affected by Borg nanoprobes, Hoshi Sato picked up some Vulcan sandworms for him from the galley and fed them to his Pyrithian bat. (ENT: "Regeneration")