Costume

Palette swaps, also known as costumes and color changes, are a feature in Super Smash Flash 2 and Yeah Jam Fury that allows characters to swap between different appearances with different sets of colors and outfits.

In Super Smash Flash 2
Every character in Super Smash Flash 2 has at least eight different palette swaps, including the default design, with the main purpose of distinguishing players that are using the same character and used for personal preference. This is one of the many features carried over from the Super Smash Bros. games to Super Smash Flash 2 and, as such, was absent from the original Super Smash Flash.

Most palette swaps are simple tints and hues applied to the default design of the character, with each one meant to represent a separate color or style. However, certain characters also have palette swaps where they wear different kinds of clothing or accessories, such as hats and bows which often keep the trend of separate colors.

Players can choose their palette swaps from the character selection screen. In Free for All matches, players can select any of the palette swaps their characters have available, and each one can only be picked by a player at a time. In Team Battle, characters can only change color by changing teams (which only supports three colors: red, green and blue). If team members choose the same characters, the second will have a lighter tint applied to their character; a third member will have a darker tint.

In Online matches, if two players select the same palette swap, the host is forced to use the default color while the other player keeps the color they have chosen. If both players pick the default color, the host uses the secondary color of the character.

List of palette swaps
Most characters have slightly altered hues for their Team Battle costumes; unless the difference is significant, team colors won't be listed as an alternate color.

In Yeah Jam Fury
After clearing the final level of Yeah Jam Fury, China Shop, the player unlocks the option to change the color palettes of each playable character. When activated, each character will be wearing a golden turbian, a golden jacket, green earmuffs, a white shirt, and black pants. In Style-themed and Desert-themed levels, their palettes are unaffected. Much like in SSF2, these changes are purely cosmetic and do not affect gameplay.

Trivia

 * Many of the palette swaps in SSF2 have garnered strong controversy from the community due to their simple nature of being hues and tints applied to the characters' sprites, causing them to appear unnatural and unappealing.
 * Although palette swaps would be improved with updates to the game, former developer Alex Tid Knowles released a video to his YouTube channel in 2015 to explain the process of making palette swaps and how the developers are only able to do so much with the limitations of Flash, as more complex palette swaps would require far more data.
 * currently has the most palette swaps of any character in SSF2, with 20 in total.
 * In SSF2, palette swaps were first presented in v0.4a of the demo as simple tints ranging from red, green and blue, solely for the purpose of Team battles. This remained the same until v0.9a, which incorporated more complex color changes, replacing the old tints.
 * Selecting and  in the same match in SSF2 can result in them both using the same palette swap, simply by selecting them on the character selection screen. Then, by using Transform, there can be two identical Zeldas or Sheiks in the same match.
 * It was originally planned for Yeah Jam Fury to include additional unlockable palette swaps, including one that switches the main characters Yeah, Jam, and Fury to female counterparts Yeanna, Jammi, and Furia, respectively, with each having a unique voice. They were intended to be used in the Steam and Wii U release of the game before it was cancelled in favor of the follow-up, Yeah Jam Fury: U, Me, Everybody!.
 * Although YJF only contains one set of traditional palette swaps and its follow-up contains none, the physical appearance of the three playable characters automatically changes in certain themes in both games.
 * Unlocking the palette swaps in YJF unlocks the Unlocked Cool Clothes! trochieval.