Omnath, Locus of Creation

When Omnath, Locus of Creation enters the battlefield, draw a card.

Landfall — Whenever a land enters the battlefield under your control,
If this is the first time this ability has resolved
this turn, you gain 4 life.
If it's the second time, add {r}{g}{w}{u}.
If it's the third time, Omnath deals 4 damage
to each opponent and each planeswalker
you don't control.