I used his toon self from various pictures involving his music.
Similar to Wario, strong, good jumper, but quite light.
B: Dance Moves
Hold B and he'll dance. While holding B, soundwaves will hit random directions, but moving the controls at a certain direction will make the waves go at that direction.
Side B: Cart Ride (Right Now) [link]
Psy gets in a cart and will dash at opponents. It will also carry items on his way, except boxes, barrels, and bombs. Stopping the cart will make him go on the position, and (if had any) the items that he carried along the way.
Up B: Audience Platform Carry (It's Art) [link]
Psy will ride on a platform with hands carrying him, he'll go to the direction like Lucario's extremespeed. It does damage, but it's quite slow.
Down B: Box of Item's Owners (Dream High 2, never watch the series, but there's an episode where Psy appears: [link]
Psy pulls out a box. Similar to Mr. Game and Watch's Oil Panic, it will gain projectiles from other enemies. Like Cart Ride, it'll gain items, except the ones mentioned before. After three special projectiles, he'll throw them at the opponents, and it's quite powerful.
Final Smash: Oppan Gangnam Style
Psy does his famous song and dance, like Donkey Kong's Final Smash, sound waves will appear from his surrounds. Timing the music with the attack button will make the waves bigger and stronger, and eventually a small third and fourth wave will appear.
I might do another celebrity for my Super Smash Bros Lawl.