 In addition to duetting on " Somebody That I Used to Know " , Bomer and Criss perform a mashup of the Duran Duran songs " Hungry Like the Wolf " and " Rio " early in the episode . Criss also sings Christina Aguilera 's " Fighter " . These songs were released as singles available for digital download , along with two others from the episode , " Up Up Up " and " I 'm Still Standing " , both performed by Agron and McHale . 
