Monstrous bloodshed

Evan doesn't want to stay with his Aunt Kathryn. She's just too strange, almost a real witch - otherwise why would she have a black cat and a huge library of spellbooks? But the real horror begins when Evan and his new friend Andy, just for fun, buy a jar of mysterious goo called "Monster Blood" from an old toy store. The viscous green slime starts growing by leaps and bounds, and it also seems to be alive... and deadly!