Winter

Treefolk creatures you control have Deathtouch.
Treefolk creatures you control get +0/+1.
If all four seasons are on the battlefield negate
their effects. Instead, all Treefolk creatures gain
Haste, Firststrike, Hexproof, Deathtouch,
and +0/+10.
Return this card from the graveyard to your
hand when you play a land.
"Winter, the season of decay." -Tim