Ghidorah , Planet-Eater

0: Play this card by Riding a Kaiju or Mutant whose combined cost is 6 or 7.When this card dies , Return it to the Drop Zone.
0: This card enters the battlefield with 6 Slumber Counters on it . Every turn , remove a Slumber Counter.
+6: When this card has 0 Slumber counters , You can sacrifice it : Play two Kaiju from your deck with costs equal to this card's cost.