SuperBooser: METAL!
New Hair: Extra spiky.
New Emote: AIR GUITAR!
New Power: Summon Roadie. Sort of like a Demon, but no real effect.
My idea for a booster is similiar to above, sort of a music themed with emotes such as guitar, air guitar, drums, air drums, singing, with dances as well, breakdance, headbang and costume pieces like tattoos, piercings, and spiked hair with streaks in it, sort of a punk like look and I'm thinking for the power it would be a hoverboard that looks like a guitar and the speeds inbetween hover and fly pool power.
Alot of my friends agree this would be a great booster to add.