The Gargoyle is a creature from the short story I'm Telling!.
It's a creature that has the power to use it's saliva to turn anything to stone. Adam discovers it, and notices its powers. He takes some of its salivia in a water gun, and he tests it on a tree, and it works, but he uses the saliva on his sister, turning her into a statue. Adam later fought the gargoyle and managed to turn it back into a statue and unfroze his sister. However, he froze her again after she said she would tell on him.
The Gargoyle can be found in the master bedroom in the Dead House, the player must put it's saliva in a container and use it against the Monster Blood.