Cherubi

Whenever a Forest comes into play under your control, you may return Cherubi from your graveyard to the battlefield.
Graft 1 (This creature enters the battlefield with a
+1/+1 counter on it. Whenever another creature enters
the battlefield, you may move a +1/+1 counter from
this creature onto it.)
Sacrifice Cherubi: Return target creature card
with mana value X or less, from your graveyard
to your hand. X is half the number of cards in
your hand rounded down.