For some reason I couldn't get a good picture of this shirt... Derpy is trying to eat the Sonic Screwdriver, so her eyes are glowing blue, and there are actually small rays of light coming out her eyes, and the open parts of her mouth.

Dr. Whooves and Derpy Hooves belong to Habro

The Sonic Screwdriver and the T.A.R.D.I.S. belong to whoever owns the Dr. Who franchise