Keldon Oasis
Artifact Land (Rare)

(Keldon Oasis isn't a spell.)

Keldon Oasis enters the battlefield tapped unless you pay 2.

X, Tap: Tap target artifact with converted mana cost X or less.

Tap: Add R or G to your mana pool.

Put Keldon Oasis on top of your library: Add 1 to your mana pool.

John Grant West