The Master (The TV Movie)

the Master inhabited a snake-like creature variously called a morphant or deathworm. In this form, he then possessed a Human, Bruce.

Preparations
The Master had earlier prepared for his execution on the Dalek homeworld Skaro by transferring his consciousness to a new host.


 * Though both accounts credit him with having done so deliberately, one claims that he absorbed a deathworm (EDA: The Eight Doctors), another that he used a Skarosian life form called a morphant (DWM: The Fallen)

Whichever method he actually used, his consciousness survived the death of his physical body and escaped both the casket in which the Doctor stored his ashes and escaped from the TARDIS, attacked it, causing a timing malfunction, and when the ship had materialised in San Francisco in the last days of 1999. (DW: Doctor Who: The TV Movie)

Takeover
Opening the door of the TARDIS, the Doctor got hit in the crossfire of a shooting and got picked up by an ambulance. Hiding in a bag inside an ambulance, he laid and wait as Bruce drove the ambulance's driver drove the Doctor to hospital. After Bruce had gotten home, the Master jumped down Bruce's throat, killing him physically and making him into a living corpse.

The Master, posing as Bruce, attempted to keep an eye on the Doctor. He befriended Chang Lee, a young local who had found the TARDIS key, with the eye to winning him over to his side. With Chang Lee, he entered the Doctor's TARDIS and regaled Chang Lee with stories of the Doctor's supposed villainy. He planned to open the Eye of Harmony and cause mass destruction. (DW: Doctor Who: The TV Movie)

Defeat
In the meantime, after dying, the Doctor regenerated into a new incarnation. Greeting the Doctor in his own TARDIS, he used a form of mind control on the Doctor's ally, Grace. Following a struggle at the lip of the Eye of Harmony, the Master fell into it. The Doctor claimed that he had been "eaten" by the TARDIS. (DW: Doctor Who: The TV Movie)

He was, however, rescued by Esterath. (DWM: The Glorious Dead)

Behind the Scenes
Gordon Tipple played the Master's previous incarnation, who appears only in a cameo and does not speak. Though the script to Doctor Who: The TV Movie referred to the Master in this form as a "morphant", this name does not appear onscreen.