Made for a pony icon on my storyboard template.
If (when?) Doctor Whooves is ever a unicorn, I am sure his horn would be his sonic screwdriver.
(PS: this was stupidly easy to build in Flash, after constructing the Doctor for the BTTF picture- just had to create a new cheek, new eyebrow, teeth, and the horn/glow. Then just rearrange the parts)
The font is "Prime Minister of Canada", an allcaps font by Ray Larabie. :3