Dr Cadabra

 was a magician who performed his act for both children and adults. He was hired by a office worker for the office's Christmas party.

When Dr Cadabra arrived at the office building, he was pulled into his mirror prop, not knowing its surface had been covered in a temporal meniscus by an alien. The Sixth Doctor and the office worker tried to rescue him, but since they couldn't, he told them to break the mirror. They did so, with him trapped inside. (PROSE: Dr Cadabra)