Lost. Alone. Far From Home.
Pounders are simple creatures in some ways: They want fresh meat, and they get it by running into that meat, knocking it loopy and dragging it away – old-fashioned!
They resemble a cross between humans, and crystals, and turtles. Not fast-moving, but their crystalline carapaces make actually hurting them difficult.
They enjoy eating human flesh, and are not particular about the human in question being dead first.