A 1969 animated short feature, created and directed (and just about everything else) by Canadian animator Marv Newland.
Clocking in at less than 2 minutes, the clip consists predominantly of a string of credits, mostly glorifying Newland: e.g. "Directed by Marv Newland; Written by Marv Newland; Cinematography by Marv Newland; Marv Newland by Mr. and Mrs. Newland, etc.," before commencing the all-too-brief battle scene between the giant radioactive lizard of Japanese sci-fi fame and the peaceable animated fawn of Disney's family-themed classic. The clip is available both on videotaped animation compliations and from a few sites on the web, and also appeared in 1999's "Spike and Mike's Classic Festival of Animation."
"Bambi Meets Godzilla" was one of Newland's first animated projects. He went on to found the (now defunct) Vancouver-based animation company International Rocketship, and continues to work in animation to this day, most recently having directed episodes of the Eddie Murphy claymation series "The PJs" and the cable cartoon series "Duckman."