New Biome: Flat Lands

A sub-biome in the plains which is very flat and there is no grass and no mountains and nothing spawns and nothing is there.

Or is there...?

Underneath the flat lands there is a Big dark cave with undead mobs roaming about even zombified Illagers! Houses are broken and the grass is dead. Dangerous and ominous. A player with fine diamond armor mines unsuspectingly under the flatlands. 

"Ooooh, a cave." He says as the stone crumbles in front of him revealing a cave. He sees houses in the distance with undead everywhere. Except these mobs are not normal, they look more like people in which there life was sucked away. He looked on the ground. A very suspicious looking sand was everywhere. He stepped on it. It began to slow him down and give him a sickness that made him cough and fall. Distant mobs heard the noise and had come to investigate. They lumbered towards the noise. "Help!" He said on the ground. He got up brushed off the sand which stung when he touched it. The Undead swarmed around him as he ran back up the stairs he had mined away. He quickly reburied the mine and sat down tired. He got a piece of pork chop from his inventory and moved on. Unaware of what he had discovered.