Spirit of the Forest

Vigilance, Trample
Whenever Spirit of the Forest attacks, exile the
top card of each player's library. You create a
number of 0/1 Green Plant tokens equal to the
total converted mana cost of cards exiled this
way.
{t}: Choose target card in exile. You may cast
that card this turn and you may spend mana as
though it were mana of any type to cast it.