Spawning Pool

Spawning Pool enters the battlefield tapped.

[Tap]: Add [B] to your mana pool.

[1][B]: Spawning Pool becomes a 1/1 black Skeleton creature with "[B]: Regenerate this creature" until end of turn. It's still a land. (If it regenerates, the next time it would be destroyed this turn, it isn't. Instead tap it, remove all damage from it, and remove it from combat.)