The Urlfjord, Boreal Labyrinth

When The Urlfjord, Boreal Labyrinth enters the battlefield, sacrifice a land.
{t}: Add {w}{u} or {c}{c} to your mana pool.
{w/u}, {t}, Sacrifice a land: Tap target permanent. It doesn't untap during its owner's next untap step.
"Ice and snow will become the tomb of all lost in the frozen wastes." - Urlfjordian fable