Devouring Monstrosity

Cumulative upkeep-Pay 1 life
{w}{b}{t}: Exile target non land permanent with converted mana cost that is less than Devouring Monstrosity's power, then put a +1/+1 counter on Devouring Monstrosity.
When Devouring monstrosity leaves the battlefield, return all permanents exiled with it to the battlefield under their owners control.