Hershel

It is a stone-scorpion. Appears in the episode "Finding Hershel". At first sight it is only a stone. Yin and Yang should be responsible to care for her by order of the Master Yo. However, Yang had enough and called him "stupid." That made Hershel became a scorpion sting all who call him stupid, making a giant monster (that happens to Dave and Coop).