Prepare for the day everyone fears...with a nice, warm cup of coffee. This 11 oz. Friday the 13th Jason Voorhees Morphing Mug transforms from black to full color as hot liquid is added! Watch as the heat-activated process reveals a hidden image of Jason in vivid colors. Hand wash only. Not safe for dishwasher or microwave. Measures approximately 3 3/4-inches tall x 3 1/8-inches in diameter.