Gruul, Keeper of the Grove

Whenever you cast a creature spell with mana
value greater than the number of experience
counters you have, you get an experience counter
At the beginning of your upkeep, look at the top
X cards of your library, where X is the number
of experience counters you have. Cast up to one creature spell without paying its mana cost, then
put the rest on the bottom of your library in any
order.