This mug depicts the skull of Anakin Skywalker inside a broken and burnt Darth Vader helmet. The helmet has a matte black glaze, while the skull has a bone-texture white glaze.

From Beeline Creative:

“You don't know the power of the dark side! The Darth Vader ‘Dark Side’ tiki mug is unlike anything we've ever produced for Star Wars under the Geeki Tikis® brand. This 28oz. mug is a limited edition of 500pcs and features a matte black glaze on the iconic helmet with white detailing on the skull. This impressive ceramic mug measures 6in tall x 6.5in wide x 5.5in deep. The Dark Side mug will debut at San Diego Comic-Con with a limited amount of units reserved for future con(s) and/or online purchase (at a later date).”