This is a mug shaped like a dragon, named Drogon.

Drogon is one of the three dragons born in the wastelands beyond Lhazar, along with his brothers Rhaegal and Viserion. He is named after Daenerys's late husband Khal Drogo. He can be distinguished by his black and red colored scales, and red-black wings. He was also Daenerys's personal mount.

This is one in a series of Game of Thrones ceramic mugs. Many of these same designs were also produced as plastic mugs with straws and lids.