Katy Perry recently told Jimmy Kimmel that her goal for the video for her new single 'Birthday' was to not be sexy or glamorous.  So the pop star relied on makeup and special effects to transform into five of the worst birthday wishers ever.  It's not the Katy we're used to seeing, but it is still the same Katy that doesn't take herself too seriously.  'Birthday' is the catchy, fourth single from Katy's album Prism.