Found it!

Whenever I watch Serenity, I resolve to find a copy of the commercial that makes River go crazy in a bar and beat up a bunch of people. Clearly somebody made a complete commercial for use in the movie, so it must be floating around somewhere on the web. Right? Right.

The search proved more challenging than I expected. Wasn’t until I noticed one of the characters refer to “the oaty bar” that I managed to find it.

[reviewing security footage of the bar]

Mal: Go back further.

Mr Universe: No… [typing]

Mal: Uh…please?

Mr. Universe: Oh Mal. You’re very smart. Someone is talking to her. [focuses in on the commercial]

Wash: The Oaty Bar?

Mal: Subliminal… It’s a subliminal message broadwaved to trigger her.