Koopa Ao
A character resembling Bowser with blue coloration to him.
Overview
A palette swap of Bowser appears in Super Mario Bros.: The Lost Levels as well as the Lost Levels portion of Super Mario Bros. Deluxe, with some blue coloration. This character does not take his place at the end of castle stages, and in one instance, actually shows up right before fighting the real Bowser. Furthermore, in the first two instances he is fought, he does not turn into a standard enemy when defeated with fireballs, suggesting it is genuine.
Various contemporary guidebooks suggested various identities to this "other" Bowser. The Zen Super Mario Ohyakka indicates that he is Bowser's younger brother, and a member of the royal Koopa family. Japanese Wiki sources also say his name is Bibinba - bibimbap, one of the names Shigeru Miyamoto had intended on giving Bowser, and also a name based on a Korean dish like Koopa was. The later publication Mario Character Dai Jiten Perfect-ban suggests that this blue Koopa is one of the False Bowsers, a sentiment echoed in the "Tips" for Super Smash Bros. for Wii U, in which a blue-colored palette is available for Bowser. However, 2015's 30th Anniversary Super Mario Bros. Encyclopedia simply states that the blue Koopa's identity is unknown.
The Super Mario All-Stars and Super Mario All-Stars + Super Mario World version of The Lost Levels does not use a blue-colored Bowser.
Other Appearance
A blue palette swap for Bowser appears as his player 2 color in the Super NES version of Yoshi's Cookie. A blue palette is also available in Bowser's appearances in the Super Smash Bros. series
Bowser was also shown with blue coloring in various early art, including Miyamoto's original cover art for Super Mario Bros.
