Mountain of Slumber

{1}, {t}: Add {b}, {r}, or {g} to your mana pool
Whenever you sacrifice a creature put an
awaken token on Mountain of Slumber.
At the beginning of your upkeep, if there or
ten or more awaken tokens on Mountain of Slumber, sacrifice it and put a 10/10 legendary lizard gaint creature token with trample onto the battlefield.