The Ghostbusters teaser shot to convince independent theaters to play the full movie

This short film was an ad for Ghostbusters, filmed by Bill Murray and Dan Aykroyd (in character as Drs. Venkman and Stantz) to convince independent theater operators to run the forthcoming movie itself. Film-Tech Cinema Systems tracked down the original 35mm film and scanned it.

Here's more of the unused original theme tune—but not the complete version, which apparently eludes discovery.