When Grishnákh, Brash Instigator enters the battlefield, amass Orcs 2 (Put two +1/+1 counters on an Army you control. It's also an Orc. If you don't control an Army, create a 0/0 black Orc Army creature token first.). When you do, until end of turn, gain control of target nonlegendary creature an opponent controls with power less than or equal to the amassed Army's power. Untap that creature. It gains haste (This creature can attack, and as soon as it comes under your control.) until end of turn.