Stock somewhat resembles a European Dragon. He has flaps of skin between his arms which act as wings, and his body is thin and streamlined. Stock also has three dark spots on his neck.
Stock also appeared in episode 7 of Go! Greenman. He was the seventh monster to battle Greenman. Him and Tonchiki went to a playground to terrorize the kids who were there. The kids called for their hero Greenman, using the Green Calls. The two battled in the playground, but Greenman came out victorious by utilizing his surroundings; such as propelling himself at Stock with a swing.
- Stock can spit pellets, forming a barrier around his body
- Stock can breathe a highly toxic mist
- Stock's weakest point is his chest, and when severely damaged, will cause the monster to explode