How about a tailpipe?
A fourth penis.
Well, the first three are just rubbish.
It's alright to have fourteen nipples. Thirteen is just a birth defect.
An eye on the back of my head
Wouldn't that be disorienting? Besides, who would trust a dentist, doing his work with the backside against the patient...
Chameleons can move their eyes in random directions and they arent disoriented
So, the next time I call for a time to see a dentist I should ask for a chameleon - that is reassuring. I'm sure there are lots of them available.