Role in the film
Selick is first seen meeting Elastigirl in the studio after talking with Chad Brentley on TV after Elastigirl stops a recently opened train controlled by the Screenslaver in New Urbem. When Elastigirl meets her, she tells her to bring out peace in which the Ambassador bids her to help fight against evil. Later when the Screenslaver takes over the studio, Elastigirl escapes and jumps on a helicopter via window, warning a pilot that the ambassador is in trouble. Elastigirl manages to get into the helicopter controlled by the Screenslaver as Elastigirl escorts the passengers out of the copter, alongside Selick, in which she successfully saves them.
Selick (wearing a blue dress) is later seen during a conference at the DevTech ship about superheroes being planned to be legal again in which it is suddenly taken over by Evelyn's evil plans where she and the other superheroes and passengers are being hypnotized. Later when Winston Deavor disables the screen controlled by Evelyn, she and the other victims are later saved from Evelyn's hypnosis, thanks to Winston's help.
- Her name is a play on Henry Selick, director of The Nightmare Before Christmas and James and the Giant Peach.
- During the scene where DevTech is having a conference at sea, the audio description incorrectly identifies her as another ambassador other than Henrietta Selick, though she is seen wearing a blue dress. However, the ambassador was Henrietta Selick who was present during the conference.