Thanks to Turner Classic Movies, I've just seen the 1945 version of Brewster's Millions for the first time. I was surprised to find a small animated segment within it.
The producer, Edward Small, was an independent who released this film through United Artists, a distributor that was not affiliated with an animation studio at the time. The moon's voice sounds like Billy Bletcher, voice of the Big Bad Wolf, Peg Leg Pete and other cartoon characters. That leads me to believe that the animation was done on the west coast. I have no idea who was responsible for this animation, which is frankly pretty crude. Does anyone know?
The actor, by the way, is Dennis O'Keefe.