Frank and Stan's Monster

Frank and Stan's Monster enters the battlefield tapped and doesn't untap during your untap step.
Sacrifice another creature: Untap Frank and Stan's
Monster and put a +1/+1 counter on it.
Whenever Frank and Stan's Monster attacks, destroy target creature defending player controls, then put a +1/+1 counter on Frank and Stan's Monster.
"The more flesh we give it, the stronger it gets!"
"That's the idea, Frank..."