Evolution

Is that Alien?

Nope. Just Phronima sedentaria, an amphipod that lives in the deep ocean. This strange creature is usually less than 1 inch long, so it probably isn't going to terrorize the planet any time soon.

Females of this species will capture and eat the inside of a salp (a tunicate that resembles a jelly fish) and use the bell of the now-empty salp to protect her young. When the young are large enough, they eat the salp and swim away.

Picture courtesy of:

http://news.nationalgeographic.com/news/2007/08/photogalleries/sea-creatures/photo4.html

Sources:

http://www.cabrillomarineaquarium.org/exhibits/socal-species-details.asp?id=36

http://news.nationalgeographic.com/news/2007/08/photogalleries/sea-creatures/photo4.