What is a “bias wrecker?”

Every K-pop fan typically has a favorite member of a group. In K-pop slang, this favorite is referred to as a “bias.” In fandom culture, a "bias wrecker" refers to a member of a K-pop group who catches a fan's attention with their talent, personality, visuals, etc., causing them to feel conflicted or tempted to switch their allegiance from their original bias to this new member. It “wrecks” the fan’s original relationship to their favorite. This member is referred to as the "bias wrecker."