You have to be in North Korea, doesn't work with a vpn btw

You have to run around the fountain in a way that spells luigi for 64 days,64 hours, and 64 minutes then go to the mirror room and walk in the door on the other side and jump down the bottomless pit then Luigi will jump out then fly away two seconds later.

first step, buy a nintendo ds, then, buy super mario 64 ds, and then you can unlock luigi