Unstable Fauna

Unstable Fauna enters the battlefield with X
+1/+1 counters on it.
If damage would be dealt to Unstable Fauna,
prevent that damage and remove that many
+1/+1 counters from it. Then reveal that many
cards from the top of your library. You may put
a creature with mana value equal to or less than
the number of counters removed this way into
play under your control.