The Butterflied Dimension is a Dimension where Riff inadvertently caused the end of the world.
In the storyline The Halves and Half-knots, Riff's experimentation with using the Dimensional Flux Agitator to create double-sided portals ends up sending half of the bodies of Gwynn, Kiki, and Torg to the Butterflied Dimension. There, Torg and Gwynn meet that dimension's version of Riff. He had attempted to use the DFA for a magic show, zapping a volunteer to another dimension and bringing a butterfly back in their place to create the illusion that they'd been transformed into a butterfly. However, the DFA malfunctioned and ended up replacing everyone in the world with butterflies, with no way to get them back. As a result, a bitter, drunken Riff is the last remaining person in the world.