Grab the Reins

Threaten and Fling, welded into one instant. The first mode borrows a creature for the turn with haste, the way Act of Treason and its lineage do; the second sacrifices a creature you control and hurls its power at any target. The open-ended sacrifice in mode two is what gives the card its bite: nothing forces you to feed back the same creature you stole, so the damage half stands alone as a Fling-style finisher whenever you have a board worth converting. Pay the entwine cost and both halves resolve together during the spell's resolution, top to bottom in the order printed: first you take control of their creature, then you sacrifice a creature to deal damage equal to its power. That fixed ordering is the entire trick. The borrowed creature is on your side and at instant speed by the time the second mode looks for a sacrifice, so you can hand it straight to the damage mode and point its own power back at its controller. There is no combat step in between and no chance to swing with the stolen body first; entwine never opens a window between modes, and the caster cannot rearrange them. Each half also works at instant speed on its own, the quiet upgrade over the sorcery-speed steal effects that preceded it: hold the burn as a combat trick, or grab a blocker on an opponent's turn. Modal-with-entwine was an early-era way to sell flexibility while pricing the privilege of buying both at once.