Rubblebelt Rioters 
Creature — Human Berserker
Haste Whenever this creature attacks, it gets +X/+0 until end of turn, where X is the greatest power among creatures you control.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL