Thrall, The Earth Aspect

When Omnath, Locus of Creation enters
the battlefield, draw a card.
Landfall - Whenever a land enters the
battlefield under your control, you gain 4
life if this is the first time this ability has
resolved this turn. 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.