Sparkling Caves
Artifact Land (Rare)

(Sparkling Caves isn't a spell.)

When Sparkling Caves enters the battlefield, sacrifice it unless you pay U.

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

1, Tap: Add UU, UB or BB to your mana pool. Sparkling Caves deals 1 damage to you.

Lars Grant West