Will Arnett

Film Deaths[]

Wristcutters: A Love Story (2006) [Messiah]: Commits suicide (off-screen) by stabbing himself, while leading his cult in an "ascension," shortly before his first appearance; he appears as a spirit in the afterlife for suicides, and commits suicide once again (on-camera) by stabbing himself in front of his cult yet again. (Played for comic effect.)
Jonah Hex (2010) [Lieutenant Grass]: Killed in an explosion when John Malkovich's Nation Killer weapon is tested out on his ship.

Sit Down, Shut Up: Tackin' (2009; animated) [Ennis Hofftard]: Dies momentarily of a stress-induced heart attack; he appears as a spirit in the afterlife before being revived by Sue (voiced by Kenan Thompson). (Played for comic effect.) (Thanks to Andrew)
A Series of Unfortunate Events: The Miserable Mill Part Two (2017 series) [Quagmire Father]: Burned to death (off-screen) along with Cobie Smulders after an unknown assailant sets fire to their mansion.
BoJack Horseman: Thoughts and Prayers (2017) [Butterscotch Horseman]: Killed in a duel offscreen before the events of the series. This episode is the first to mention Butterscotch’s death explicitly: in a flashback showing BoJack (also Will Arnett) and Beatrice (Wendie Malick) on their way to his funeral. The cause of death is confirmed by BoJack’s dialogue in the episode Free Churro.
Our Flag Means Death: We Gull Way Back (2022) [Calico Jack]: Struck by a cannonball which had been fired by Rory Kinnear, while taunting a seagull. The death could be due to Ewen Bremner's hex that he attempted to put on Will.