Ulamog the Eldrazi lord

When Ulamog the eldrazi lord enters the battlefield you gain 40 life.
Whenever Ulamog is tapped your opponent sacrifices 4 creatures of your choice
When ulamog attacks your opponent discards the top 30 cards of their library.
{6}Ulamog gets +12/+12 and hexproof for the rest of the game.
When Ulamog leaves the battlefield you lose the game unless you pay {6} .
If you do you win the game.