Slash (Zan in the original) is the main villain of Jibaku-Kun (as known Bucky: The Incredible Kid or Bucky: Searching for World 0) series, a creation of Ami Shibata.
Slash is actually an evil entity that arose due to the desperation of the Spaak's sister, while she remained paralyzed for several decades in the Needle Tower. He appears most often under a cover and a black hood. The first consistent appearance of Slash was in a small town of Trios (3rd world) when he turned various docile monsters into monsters troublemakers. After that, Slash went on to pursue Bucky, Pinky, Kai and Bremie. Slash resurfaced in Undicus, and turned Ashie into a troublemaker monster that absorbs all the trash you see.
In the final battle, Slash possessed the body of Spaak, and was defeated by Bucky with Pump Great Jibaki. Slash later reappeared in the shape of a dragon, who was defeated by Bucky using the twelve spirits.
Slash's main power is "The Poison Awakening", it is a dark substance that ruins everything it touches. Transforms animals, plants, and even humans into evil beings.