When Treetop Marsh enters the battlefield, you lose 1 life unless you reveal a planeswalker card from your hand.
: Add
or
to your mana pool.
Put Treetop Marsh on top of your library: Add
to your mana pool.

: Treetop Marsh becomes a 1/1 green and blue Elf creature with flying until end of turn. It's still a land.