The 16mm short film "Mickey Mouse In Vietnam" is an anti-war movie by Lee Savage and Milton Glaser, produced for The Angry Arts Festival in 1968. Long vanished, the movie has returned to YouTube. Buzzfeed has an interview with Glaser about the video's history:
Speaking of symbolism, is that why you picked Mickey Mouse in particular?
MG: Well, obviously Mickey Mouse is a symbol of innocence, and of America, and of success, and of idealism — and to have him killed, as a solider is such a contradiction of your expectations. And when you’re dealing with communication, when you contradict expectations, you get a result.
Disney is very protective of their intellectual property. Did you ever hear from them after you screened the film?
MG: No… There was some talk about Disney suing us, but I think the consequence of that — everybody realized — would have been negative for Disney and would have no benefit. And obviously no profit was made out of the utilization of the character or the film, so nothing ever happened.
Update: Adam Savage writes, "Lee Savage did not die a couple of years after Vietnam, as Milton seems to suggest. Lee Savage was, in fact my father and he directed inked and animated the Mickey Mouse film which he co-wrote with Milton. My dad died in 1999 after a long bout with Alzheimer's and was always very proud of the Mickey film."