Skrit Na

The Skrit Na are a race of scavengers from the Animorphs universe that are known to abduct and experiment on other races. The species possesses two distinct stages in its life cycle with the mature form resembling greys (they actually ARE greys in the Animorphs universe). The larval form was similar to a centipede and they produced a silken cocoon to transform. Although normally quadrupeds, they are capable of standing upright to manipulate tools. As well as abducting specimens, they also take them to their homeworld to keep them in zoos, and have been doing so for millions of years. Andalites consider them unscrupulous and know that they are occasionally Yeerk hosts.