Fang of the Pack 065/221

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