Puppet fighter

Puppet fighters are clones made of the playable characters in Super Smash Bros. Ultimate and are the main antagonists of the game's adventure mode, World of Light. They have the same abilities and appearances of the original fighters, with the addition of glowing red eyes.

History
During the beginning of World of Light, Galeem defeats every character in the universe, except for Kirby. Galeem then created empty statue-like clones in the fighters' likeness, and forced the Spirits to control the puppet fighters, allowing the lifeless puppet fighters to move. The spirits tend to posses puppet fighters that closely resemble themselves, such as an Iridescent Glint Beetle possessing a golden Squirtle These puppet fighters then spread themselves across the world. Kirby must them defeat one by one in order to free the spirits trapped inside.

When Galeem is defeated, Dharkon attacks the world, and the spirits and their puppet fighter hosts fall under Dharkon's control. Eventually, after both Galeem and Dharkon are defeated for good, all of the spirits are freed, and, presumably the puppet fighters are either left behind or destroyed.

Trivia

 * Since multiple fighters can appear in one battle, it is implied that one spirit can possess multiple fighters at once.
 * Kirby must also fight the playable characters themselves in order for them to be playable in World of Light. It is unknown whenever these are puppet fighters or not, as they are not being possessed by a spirit, but they do have glowing red eyes.