Molten Primordial

Borrow-and-swing effects are tempo plays at their core, and the design problem with stapling one to a creature has always been the body it costs you: pay enough for the effect and the body lags, pay for the body and the effect shrinks. The fix here is the until-end-of-turn clamp, which keeps the steal honest as a one-shot detonation rather than a permanent acquisition, and the multi-target shape, which lets you reach one creature from each opponent at once. That last clause is what scales the card past a duel and into a board state: in a crowded game it concentrates a table's worth of bodies into a single attack step. The haste rider on each stolen creature, plus the untap, dismantle the usual objection to borrowing blockers, that they tapped to block last turn, so everything you take can swing the moment it changes hands. Six power on the Avatar's own hasty frame joins that strike rather than waiting a turn. Where a single-target steal reads as tempo, this reads as a closing argument: take the blockers, point them and everyone else at their owners, and resolve the game before the loaned army goes home. Once it does, you keep a 6/4 that has already done its work.