Dark Stone

The Dark Stone is a object that appears in Mario & Luigi: Dream Team. It's used for granting nightmare wishes.

History
The Dark Stone, like the Dream Stone, was safe kept by the Pi'illos. The bat king, Antasma, stole the Dark Stone then the Pi'illos had to fight him to get it back. They were gone imprison Antasma in the Dream World, but before that could've happened, Antasma crushed the Dark Stone and Nightmare Chunks scattered throughout Pi'illo Island. As the Pi'illos were exposed to the Nightmare Chunks, they were petrified. All the Pi'Illos in Pi'Illo Island ceased because they were trapped in the dream world with Antasma.

Trivia

 * The Dark Stone was most likely named after the Dark Star in Mario & Luigi: Bowser's Inside Story.