A Regulan bloodworm
A bloodworm was a small, vermiform-like organism capable of directly entering the humanoid circulatory system. (ENT: "Dead Stop", "Stratagem")
In 2371, during an away mission to a planet in the Delta Quadrant, the crew of the USS Voyager discovered indigenous bloodworms, which Neelix hoped to utilize in a tartar for the crew, an idea from which Commander Chakotay attempted to dissuade him. (VOY: "State of Flux")