Fang of the Pack 

Creature — Wolf
Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.) At the beginning of combat on your turn, another target creature you control gains melee until end of turn. (If a creature has multiple instances of melee, each triggers separately.)
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL