Rockimus, Terror Unleashed

When Rockimus, Terror Unleashed enters the battlefield, destroy target artifact or creature.
Whenever an artifact or creature is destroyed
by a card effect, put a +1/+1 counter on
Rockimus, Terror Unleashed.
Partner with Dexter, Eternal Beloved (When this creature enters the battlefield,
target player may put Dexter into their hand
from their library, then shuffle.)