The Void
The Void is an inter-dimensional hole in the game Super Paper Mario. Its purpose is to increasingly grow in size and consume and destroy "all worlds" in accordance with a prophecy outlined in the Dark Prognosticus. The Void was created by the creation of the Chaos Heart, formed by Count Bleck through the forced marriage of Bowser to Princess Peach. According to Merlon, the center of The Void is where Castle Bleck is situated, or at least an area similar to such.
The Void appears as an ominous, pulsing black hole that hovers in the skies above. Its size varies depending on the dimension one is in, as each dimension is a different distance from The Void. Frequent waves of tremors indicate that The Void is becoming large enough to be destructive. When The Void finally becomes large and close enough to destroy a dimension, the tremors become earth-shattering, space begins to warp, and flashes of light consume all matter, leaving behind a stark, white realm of nothingness. An example of this occurs when the purple Pure Heart is sucked through The Void with Sammer's Kingdom and is turned to stone in the World of Nothing that remains; ultimately, Queen Jaydes of The Underwhere, with her "power over life and death", is able to restore the heart.
Aside from Sammer's Kingdom, The Void obliterates the Land of the Cragnons, Flopside, and Yold Town, while Flipside, Lineland, The Bitlands, and Castle Bleck narrowly avoid destruction. The Void is closed following the destruction of the Chaos Heart, which occurs through the voluntary marriage of Count Bleck to Tippi.