Stock bears some resemblance to the standard 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, serving as the seventh monster to battle Greenman. He and Tonchiki went to a playground to terrorize the local children, but they were thwarted when the kids used their Green Calls to call in their hero, Greenman. Greenman eventually emerged victorious due to his ability to take advantage of his surroundings, such as when he propelled 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, which, when severely damaged, will cause the monster to explode