Clone characters are characters present in a multitude of video games. Basically, they look different from one another, though have an identical or nearly identical moveset. Usually these characters are only referred to as clone characters in fighting video games, such as in the Super Smash Bros. series. The only clones in the original Super Smash Bros. are Mario and Luigi.

Super Smash Bros. Melee

Super Smash Bros. Brawl

In Super Smash Bros. Melee and Super Smash Bros. Brawl, Luigi is a "hybrid" of Mario. Ganondorf, Wolf and Lucas fall into this category in Super Smash Bros. Brawl.

Super Smash Bros. for 3DS / Wii U

In Super Smash Bros. for 3DS / Wii U, there are 3 full on clones (Virtually the same except for a couple different properties) and 2 partial clones (functionally similar but with greater variety in move properties) with Falco and Toon Link.

In addition, characters have fewer similarities though the fundamentals are pretty similar.