At the beginning of your upkeep, Mistveil Oasis deals 1 damage to target creature you control.

: Add  to your mana pool. Activate this ability only if you control a Plains.

: Add  to your mana pool. Activate this ability only if you control a Forest.

: Mistveil Oasis becomes a 2/2 white Bird creature until end of turn. It's still a land.