How, you must think, can a Sonic tattoo ever be classy? When someone uses their imagination, that's how.
A few years back, scientists got funny and named a protein that "enhances somite cell viability and the formation of primary slow muscle fibers" Sonic the Hedgehog.
Brian here has a tattoo not of the blue hedgehog, then, but a 3D representation of the protein that shares his name. Which must make for longer stories when he says "Oh, I've got a Sonic the Hedgehog tattoo", though also (slightly) less embarrassing.
A Different Sonic the Hedgehog: A Protein Tattoo [Geeky Tattoos]