Only one hit wonders have just one signature song. Anyone with any length of success has multiple, Katy's are IKAG, CG, Firework, Roar and DH, HnC is open for debate.

(I feel like its been destroyed by the hits that followed it whilst IKAG stands strong, See: Superbowl. Did anyone miss it?)
Teenage Dream is the song that best represents Katy as a musician and as a person though and so is a signature in that sense.
