Gisa, Glorious Resurrector
Legendary Creature — Human Wizard
If a creature an opponent controls would die, exile it instead.
At the beginning of your upkeep, put all creature cards exiled with Gisa onto the battlefield under your control. They gain decayed. (A creature with decayed can't block. When it attacks, sacrifice it at end of combat.)
Illustrated by
Innistrad: Midnight Hunt#103RareEnglishLegality
Rulings
Decayed represents a static ability and a triggered ability. “Decayed” means “This creature can’t block” and “When this creature attacks, sacrifice it at end of combat.”
Decayed does not create any attacking requirements. You may choose not to attack with a creature that has decayed.
Decayed does not grant haste. Creatures with decayed that enter the battlefield during your turn may not attack until your next turn.
Once a creature with decayed attacks, it will be sacrificed at end of combat, even if it no longer has decayed at that time.