Never add lactose products into a potion, especially if they’re overdue. The result was an explosion that created a toxic but non-lethal cloud of stinking smoke and additionally turned Skoodge into a slug. Don’t worry, he got turned back to normal.
Hehe, meanwhile Red and Purple just watch safely from the other side. Hopefully Zim will suffocate in there, right?
Somewhere in the afterlife, Snape is dying of a heart stroke.