Yes I hope I fixed the image now ok
It obviously needs to be a super masterpiece. Purpleace's piece of art is a decent start because it looks funny, but that is not a Freddie Mercury stache. ;<
You can do whatever your are comfortable with. Even traditional art, as long as you edit it so it maps properly.
Freeeeeeeeedom as long as it looks amazing and fits the purple/green combo.

PS: not only the stache should be pink and poisonous, the whole head should be.
Unless you can pull off a really really amazing stache