Abominable Rat

Haste
Whenever a rat enters the battlefield under your control, you may sacrifice it. If you do, put a number of +1/+1 counters on Abominable Rat equal to the sacrificed creature's power.
"They say an army marches on its stomach. In the Rakirit's case, the army goes into the stomach."
-June Wetherbee, Monsterologist