Allison's Vocals Overshadowed by Dress!

The 16-year-old looked ready for an '80's prom, swamped by a poofy red dress that matched her spiked hair, black leggings and white heels. Simon Cowell joked that the theme of the night must be Halloween -- and that Allison's outfit resembled "something out of 'The Addams Family'!"

Adam Lambert and Scott MacIntyre rose to the top of last night's show, in which the remaining nine contestants were asked to sing a song from a list of the most downloaded songs on iTunes. Lambert impressed the panel with his energetic rendition of "Play that Funky Music" -- with Paula labeling him a "genius."

Scott played the piano and crooned Billy Joel's "Just the Way You Are." Simon told the blind prodigy that he gave one of the night's best performances, while Paula said, "Of all the contestants that have graced the stage, I am most proud of you."

On the bottom, Anoop Desai failed to impress with his hip-hop performance of Usher's "Caught Up" -- which Cowell said gave him a headache. Randy said Megan Joy's performance was as boring as "watching paint dry," and former frontrunner Lil Rounds got a dose of criticism for "playing it safe" with a Celine Dion song.