3dRose 97289_4 Yellowstone NP, Bison in Winter-US51 CSL0007-Charles Sleicher Two Tone Black Mug, 11 oz, White Fill with hot liquid to transform from black to white, magically revealing image White ceramic mug with black outer surface; image printed on both sides Microwave-safe, hand-wash to preserve image A perfect gift for any occasion, Fascinate them every time by revealing a secret or surprise image