Nightmare, sometimes called Cloaked Nightmare (and eNeMeE in the English dub of Kirby: Right Back at Ya!), is the main antagonist and final boss of Kirby's Adventure and Kirby: Nightmare in Dream Land. In Kirby's Adventure, he wanted the Star Rod to destroy Popstar. King Dedede therefore hid the Star Rod to save the planet. Kirby found the Star Rod and used it to fight Nightmare. After a long battle Kirby finally defeated Nightmare and restored the peace to Dreamland.
Nightmare is also the main antagonist in the Kirby anime, Kirby: Right Back at Ya! Although he is rarely seen, save for his silhouette in the background on occasion, he is the one who creates the monsters that Kirby fights on a regular basis.