Wolfie wrote::
Well as for medical disorders, I have Dermographism, which means "skin writing", although I'm not sure of how rare it is I've only ever met one other person with it and that person was my older sister.
Basically what it is, is if you rub scratch on put too much pressure your skin it welts up (and sometimes itches badly). The welts show up very clearly and you can actually write words on your skin by lightly dragging your fingernails over it. Its extremely annoying and I don't think there is a cure for it.
My friends will actually draw on me and etch peace signs on my arms and watch it welt, it itches like heck.yeah its not much fun, some kids at school think I have a rash...
Heres a good picture I found off Google ^.^
that's really cool. great artist tool in my opinion. no offence, but that would be like a great canvas for an imaginative artist. hope i don't offend you in any way though.