Dr. Terence Wynn a.k.a. The Man in Black is portrayed by Robert Phalen in Halloween, Don Shanks in Halloween 5: The Revenge of Michael Myers, and by Mitch Ryan in Halloween: The Curse of Michael Myers.
Despite being the administrator of Smith's Grove - Warren County Sanitarium, Dr. Wynn only makes a short appearance in the first Halloween film. In it, he is seen walking with Dr. Sam Loomis towards his car. During the scene, Dr. Loomis expresses his anger that Michael Myers was able to escape from the facility the previous night. Dr. Wynn says that Michael could not have gotten far because he could not drive. Dr. Loomis says ironically "He was doing very well last night! Maybe, someone around here gave him lessons." This exchange gains additional meaning after the revelation in the sixth film that Dr. Wynn had been watching over Michael since his incarceration, and it is probably he who taught Michael Myers how to drive.
Although it was unknown at the time, Dr. Wynn made his next appearance in Halloween 5: The Revenge of Michael Myers. The film features a mysterious "Man in Black" arriving in Haddonfield, who has a tattoo identical to one which Michael has. In the climax of the film, the Man in Black, in his role as Michael's guardian, kills everyone at the Haddonfield police station with a machine gun and afterwards rescues Michael from the police station and eventually abducts Jamie who was also there. This film did not reveal the Man in Black's identity to the audience, and at the time the film went into production, the writers themselves had not decided who the Man in Black actually was.
In the sixth film, it is revealed that the Man in Black is Dr. Wynn, and that he is the head of a cult which supposedly cursed Michael into killing his whole family, therefore explaining the reason for his constant pursuit of his sister and later his niece. In the end, Wynn turns out to have been secretly using Michael's DNA to create the curse of Thorn in its purest form that he believed manifested in his genes. After failing in DNA and in-vitro fertilization experiments, tested on the female patients of Smith's Grove Sanitarium (and leading to stillborn fetuses), the experiment became a success when tested on now 15-year-old Jamie Lloyd, who gives birth to a live baby. In the Theatrical Cut, Michael kills him in an operating room along with 9 other doctors from Smiths Grove, though Wynn's death is not seen onscreen.
In the Producer's Cut of the sixth film however, Dr. Wynn and his staff follow their cult aspect more closely and planned on making Jamie's baby Michael's final sacrifice during a ritual. Tommy Doyle however interrupts the ritual and soon paralyzes Michael with rune stones, releasing him of his curse. Later, Dr. Loomis approaches the person he thinks is Michael Myers relieved that it was now all over but to Loomis' surprise, Michael has switched clothes with Wynn and left him lying there while he makes his escape into the night. Loomis takes the mask off Wynn, and a dying Wynn grabs Loomis' arm, telling him, "It's your game now, Dr. Loomis." Loomis then looks at his wrist and sees that the Thorn tattoo is now on his arm, symbolizing his new role as the leader of the Thorn Cult. Dr. Wynn is not featured in the subsequent films, which ignore the previous three films, thereby eliminating the Wynn/Thorn plotline.
Wynn makes a cameo appearance in the comic Halloween III: The Devil's Eyes, the final issue of Chaos! Comics' Halloween miniseries, which attempts to bridge Halloween: The Curse of Michael Myers and Halloween H20: 20 Years Later. In the comic, Wynn is shown running Smith's Grove, where Tommy Doyle is being held, framed for the murders of Richie Castle and Sheriff Leigh Brackett. Wynn believes that Tommy has outlived his usefulness, and he and an orderly at the institute prepare to kill him and make the murder appear as a suicide. As Wynn and his colleague close in on Tommy in his cell, preparing to sedate him, Tommy fights back and beats the orderly unconscious, knocks Wynn aside and escapes. Wynn later kills the orderly, frames Tommy for the crime and appears at the end of the comic, visiting Laurie Strode, who has gone insane, in Smith's Grove.
- Sheriff Ben Meeker - Shot offscreen by Dr. Wynn
- Cop 1 - Shot offscreen by Dr. Wynn
- Cop 2 - Shot offscreen by Dr. Wynn
- Cop 3 - Shot offscreen by Dr. Wynn
- Cop 4 - Shot offscreen by Dr. Wynn
- Cop 5 - Shot offscreen by Dr. Wynn
- Cop 6 - Shot offscreen by Dr. Wynn
- Cop 7 - Shot offscreen by Dr. Wynn
- Deputy Tony - Shot offscreen by Dr. Wynn
- Wesley Krug - Unknown by Dr. Wynn