Finish 50cc. I did it that way. By the way, I also got golds on every cup.
You can unlock King Boo by playing the Time Trial for the Ghost Raceway.
50cc star cup
Win the 50cc Star Cup.
King Boo's fourth kart is the Aero Glider also known as the Jetsetter. To unlock it, you need to attain at least 1 Star Rank for all 150cc Retro Grand Prix Cups
Win 1st place in Mirror Mode Star Cup.
king boo toad and toadettee and peaty pirahna
Quite easy. Just beat the 50 CC Star Cup.
You can't unlock him. You can only play as "King Boo" on "Mario Kart Wii".
i don't know but try winning all cups on mirror mode
if you win the star cup you unlock king boo but that's it
finish the star cup on mirror mode ok ok that's how i pretty sure
You can't unlock Boo, but you can get a trophy for him, and many different stickers.