I may be wrong about this, but when Valkyrie falls off the ramp of her spaceship, she lands on the carcass of a funny looking creature... I believe that this is a Bilgesnipe that Thor mentions in the first Avengers movie.
THOR: We on Asgard pretend that we are more advanced, but we, we come here battling like Bilgesnipe.
COULSON: Like what?
THOR: The Bilgesnipe, you know; huge, scaly, big antlers. You don't have those?
COULSON: Don't think so.
THOR: They are repulsive, and they trample everything in their path.