Withering Boon

As an additional cost to cast this spell, pay 3 life.
Counter target creature spell.

Teferi’s Curse

Enchant artifact or creature
Enchanted permanent has phasing. (It phases in or out before its controller untaps during each of their untap steps. While it’s phased out, it’s treated as though it doesn’t exist.)

Polymorph

Destroy target creature. It can’t be regenerated. Its controller reveals cards from the top of their library until they reveal a creature card. The player puts that card onto the battlefield, then shuffles all other cards revealed this way into their library.