Howlers are the alien shock-wave troops of the nearly-omnipotent Crayak, from the fictional book series Animorphs. They are vicious creatures with cracked black skin that looks like hardened lava; beneath the black, in the cracks and creases of the flesh, are bright, red lines. They have a sort of bearing half-way up their torsos which allows them to turn their upper body all the way around and keep the sharp, Wolverine-like claws on the backs of their hands in the fight. Their eyes are large and expressionless, although quite remarkable not only because of their bright, robin's egg blue color, but because of their unique ability to see through the bodies of their prey, making major organs visible and vulnerable. Their worst weapon, by far, is their howl. It targets mainly intelligent, complex brains, but the sheer force of the cry alone can destroy any creature who hears it for a long enough period of time.

Being the tools of Crayak, this race's sole purpose is to travel through the universe and destroy peaceful civilizations. But while Howlers may seem brutal in their killings, they are in fact unaware of the severity of their actions. Howlers are not born — they are manufactured. And after three Earth years of childhood, they die. A collective memory among the species leads the childlike Howlers to believe they are playing a game, a game that cannot be lost — for, while defeat has indeed taken place in the race's history, Crayak has put forth an effort not to allow those memories of defeat to poison the collective pool.