


The Hyperiid amphipod lives in a unique dwelling. It carefully hollows out the body of a salp (which resembles a jelly, although it is actually a chordate) to live inside. It is careful to leave just enough tissue that the salp remains alive and does not begin to decompose, then lives out the rest of its days inside the body. This creepy little guy was one of the inspirations for the iconic monster in the Alien films.
Woah, freaky.