Citadel of Prav

Citadel of Prav enters the battlefield tapped.
{t}: Add {w}, {b}, or {g} to your mana pool.
{b/g}{b/g}, {t}: Create a 1/1 black Skeleton creature token with "{b/g}: Regenerate this creature."
It may look unwelcoming, still, its residents
know how to show guests a good time.