Have a friend dress up in cosplay/visual kei/anything weird. It can be anything you like, for example:
Amane Misa - Death Note
Yuna - Final Fantasy
No, don't go as Pedobear... really...
All dolled up? Now go to a public place, preferably a coffee shop where there are alot of people. Order 2 cups of coffee for yourselves and just chat normally. IMPORTANT: the one in cosplay should not be the one ordering and he/she should not touch their drink.
Green & Co in Leederville, Perth would be a perfect place for this setup.
After about 15-20 minutes, everyone in that area should've noticed both of you. Look at your friend and say:
"I wish you were real so everyone can see you!"
There you go, how to mindfuck a group of strangers =P
VERY IMPORTANT NOTES:
Don't laugh after STEP 3.
For extra dramatic scene, start crying and running out of the restaurant leaving your "friend" behind.