Lairn, the Far Wandering

Landfall - Whenever a land enters the battlefield under your control, put an explore counter on Lairn.
Remove three explore counters from Lairn: Choose One -
- Exile target creature. It's controller gains life equal to it's power.
- Exile target artifact or enchantment.
- Reveal the top card of your library, gain life equal to it's converted mana cost, then put it into your hand.