Jeering Instigator

The morph trigger hides a Threaten on a timer the opponent cannot see coming. Face down, this is an anonymous 2/2 holding ground, nothing worth planning around, until the unmorph flips it into a stolen attacker mid-combat: the target untaps, gains haste, and swings before returning at end of turn. The difference between this and a hardcast Act of Treason is information asymmetry. Threaten effects announce themselves; you tap the mana, and the opponent knows their creature is about to walk across the table and plays around it. Morph launders that intent. The borrowed creature reads as a stranded blocker right up to the instant it stops being theirs, which turns the steal into ambush rather than declaration. The "if it's your turn" clause is the restriction that pays for the surprise: the theft only fires on your own turn, so this is a way to build an attack, not a way to snatch a defender away from an incoming alpha strike. And since the borrowed creature comes home when the turn ends, the steal invites a sacrifice outlet to cash the theft in before it reverts: feed the borrowed body to the outlet mid-turn and the opponent never gets it back, the standard follow-through on temporary-theft effects. It is a precise demonstration of how morph can sell a tempo swing the printed rate would never justify: a 2/1 that, for the cost of a face-down setup turn, doubles as a combat-rewriting heist.