Regnir, Expeditious Outrider

First strike, trample, haste
When Regnir, Expeditious Outrider enters the battlefield, bolster 3. You can't choose Regnir when you bolster this turn. (If Regnir has the least toughness among creatures you control, choose the creature with the second least toughness instead when you bolster this turn.)
At the beginning of the end step, return Regnir
to its owner's hand.