Counter target spell, activated ability, or triggered ability. (Mana abilities can't be targeted.)
"It is technically an ooze, but its lifespan measures only seconds. In that short time, its appetite for magic is extraordinary."
—Simic research notes
![Voidslime [Ravnica Remastered]](http://www.cardmerchanttakapuna.co.nz/cdn/shop/products/dae802a1-b4c3-5c9a-ab8c-4f367a636ff6_5bbdad78-e383-4af3-967c-82b6d31d0e9d.png?v=1706909764&width=1445)