The Cycloids are not actual characters, but rather composites of several characters without any specific form. The Cycloids consist of Cycloid-β (a.k.a. Cycloid Beta), who is a blue 3D-model of a human male with no facial features and Cycloid-γ (a.k.a. Cycloid Gamma) who looks similar to Beta except that Gamma is a wireframe model. Both use attacks borrowed from other characters and don't speak. Their origins are unknown.
Cycloid-β borrows attacks from Kairi, Blair, Skullomania, Pullum, Allen, Ryu, Chun-Li, Akuma, Doctrine Dark and Garuda, and its attacks are performed via "rolling" motions (such as QCF+P).
Cycloid-γ borrows attacks from Ken, M. Bison, Pullum, Guile, Darun, Skullomania, Blair, Chun-Li, Cracker Jack, Akuma and Garuda, and its attacks are performed via charging motions.
Cycloid-β returns as an unplayable character in Street Fighter EX2 Plus as a dummy that players can beat up upon in certain bonus rounds, training modes, and when they beat the game.