While staying with his weird great-aunt Kathryn, Evan visits a funkyold toy store and buys a dusty can of monster blood, It's funto play with at first. And Evan's dog, Trigger, likes it so much,he eats some!But then Evan notices something weird about the green slimy stuffit seems to be growing. And growing. And growing. And all that growinghas given the monster blood a monstrous appetite....