Avengers Assemble

At the beginning of your upkeep, put a muster
counter on Avengers Assemble. Put a +10/+10
counter on each creature you control and a
+30/+30 counter on each legendary creature
you control. When Avengers Assemble has five
muster counters on it, search your library for any
number of legendary creatures with CMC of 5 or
less and put them onto the battlefield without
paying mana cost. Exile Avengers Assemble.