President Obama had a fun-filled night celebrating his last Halloween in the White House with Michelle on Monday, where the president and first lady not only danced to Michael Jackson's "Thriller," but also paid homage to another iconic singer. While passing out candy to group of young trick-or-treaters, the president spotted an adorable, miniature version of Prince coming down the line to get a treat. "Hey, Prince! What's going on man?" he greeted the purple-clad little boy, before breaking into the chorus of Prince's 1984 classic "Purple Rain." Luckily mini-Prince's uncle, Gary Williams, was there and caught the whole thing on tape. "When @BarackObama sees your nephew dressed as Prince & starts singing 'Purple Rain!' Unreal!," Gary wrote on Twitter. "Thank you @POTUS & @MichelleObama!"