At the beginning of your end step, if you didn't cast any spells this turn, Mire Wildwood deals 1 damage to you.
When Mire Wildwood enters the battlefield, put a land you control on the bottom of its owner's library.
: Add 
to your mana pool.

: Mire Wildwood becomes a 2/2 black and green Rat creature with trample until end of turn. It's still a land.