The Ur-Dragon

When this creature enters, look at the top X cards of your library, where X is your devotion to blue. Put up to one of them on top of your library and the rest on the bottom of your library in a random order. If X is greater than or equal to the number of cards in your library, you win the game. (Each U in the mana costs of permanents you control counts toward your devotion to blue.)

Add RRR.

(T: Add R.)

T, Sacrifice this token: Add one mana of any color.

Whenever you tap a Forest for mana, add an additional G. +1: Put three +1/+1 counters on up to one target noncreature land you control. Untap it. It becomes a 0/0 Elemental creature with vigilance and haste that's still a land. −8: You get an emblem with "Lands you control have indestructible." Search your library for any number of Forest cards, put them onto the battlefield tapped, then shuffle.

Landfall — Whenever a land you control enters, add one mana of any color.

If it's not your turn, you may exile a black card from your hand rather than pay this spell's mana cost. Destroy all creatures that entered this turn.

Other Cats you control get +1/+1 and have lifelink. (Damage dealt by those creatures also causes you to gain that much life.) When this creature enters, create two 1/1 white Cat creature tokens with lifelink.