Gwenboki Caverns

{t} add {b} or {r} to your mana pool
When Gwenboki Caverns enters the battlefield,
you may have it deal 2 damage to you.
If it does, it comes into play untapped, otherwise,
it comes into play tapped.
Stretching from the Niebo Mountains to the
borders of Dovac, this expansive cave system lies
unbeknownst to most of the denizens of Jeziora