Monster Blood IV — R.L. Stine

Evan Ross can't forget about Monster Blood-the evil green slime that never stops growing. It can turn ordinary pets into ferocious animals and twelve-year-old kids into freakish giants.But now there's a new kind of Monster Blood in town. It comes in a can just like the others. Only difference is this slime is blue instead of green. And instead of just growing, it's multiplying-into terrifying blue creatures with razor-sharp teeth...