Choose one â€”
â€¢ Until end of turn, you gain control of target creature and it gains haste.
â€¢ Sacrifice a creature. Grab the Reins deals damage equal to that creature's power to any target.
Entwine (Choose both if you pay the entwine cost.)
If you pay the entwine cost, you can sacrifice the creature you gain control of with Grab the Reins.
If you choose the â€œsacrifice a creatureâ€ mode, you choose the target of the damage on announcement, but donâ€™t choose what to sacrifice until resolution. You must sacrifice a creature when Grab the Reins resolves, even if you donâ€™t want to. If you donâ€™t control any creatures at that time, Grab the Reins deals no damage.
If you cast this with Entwine, you donâ€™t get priority in the middle of resolution. You canâ€™t steal something, do anything (like attack with it), and then sacrifice it.