Gau, Feral Youth

Rage — Whenever Gau attacks, put a +1/+1 counter on it.
At the beginning of each end step, if a card left your graveyard this turn, Gau deals damage equal to its power to each opponent.

Lagomos, Hand of Hatred

At the beginning of combat on your turn, create a 2/1 red Elemental creature token with trample and haste. Sacrifice it at the beginning of the next end step.
{T}: Search your library for a card, put it into your hand, then shuffle. Activate only if five or more creatures died this turn.