I can find next to no information on this bizarre looking online-only title that dropped in JP back in 2008 and went offline in 2009. It has Rival Schools characters in it (as well as others from Japanese media). You can play as a "brown skinned, short-haired figure in a suit" (https://kotaku.com/president-obama-clone-brings-chocolate-avatars-to-stree-5146822)...
...as well as customize your fighters with new body parts and accessories, like a fun squid hat offered as part of a cross-promotion with a company that made (makes?) squid USB drives.
Oh, it's also played using only a mouse.
Street Fighter Online: Mouse Generation (ストリートファイター オンライン マウスジェネレーション) is a fighting game produced by Daletto (a joint venture of Capcom and Games Arena) in association with Revoltech (an action-figure company), released for the PC in 2008. The game uses a PC mouse for combat, and the characters are customizable to some degree. The player chooses between characters which are action-figure versions of Street Fighter characters, and licensed characters based on novels, manga and anime. (https://capcom.fandom.com/wiki/Street_Fighter_Online:_Mouse_Generation)
Has anyone played this? Is it still possible to find anywhere? Just look at this.