The Nega-Wisps are a sub-breed of Wisps that appear in Sonic Colors. Unlike the other types of Wisps, the Nega-Wisps do not occur naturally. Instead, they are created when regular Wisps are drained of their own Hyper-go-on, mutating them into Nega-Wisps. Normal Wisps turn into either Purple Wisps or Violet Wisps, regardless of their type, while Mother Wisp turns into Nega-Mother Wisp.
While each different in appearance, Nega-Wisps share certain unique characteristics. After their mutation, they become darker in color, turning either purple and violet, they lose their eyes, and they gain sharp mouths, which gives them a more sinister appearance in comparison to other Wisps.
Unlike normal Wisps, who have playful personalities, the Nega-Wisps are rather violent and have in most cases degraded into a more animalistic state of mind. Even with Tails's translator, the Nega-Wisps were far too mutated to be understood. As a side-effect of their mutation, the Hyper-go-on generated by the Nega-Wisps turn out corrupted, resulting in a darker and negative type of this energy.
However, despite their behavior, Nega-Wisps are not evil by nature, and do not like Dr. Eggman like the rest of their race. As such, in the cases of Purple Wisps and Violet Wisps, they were happy to side with Sonic and aid him when needed, while defying Eggman.
During the events of Sonic Colors, thousands of Nega-Wisps came into being as a by-product of Dr. Eggman's operations, where the scientist drained his captive Wisps of their Hyper-go-on in a shot for world domination. Created from inside a factory in Asteroid Coaster where the Wisps had their Hyper-go-on sucked of them, the Nega-Wisps created were forced to carry out Eggman's plans after their creation. In the end, all of the Nega-Wisps were returned to normal by the unaffected Wisps, with the exception of Mother Wisp, who was returned to normal by Super Sonic.