Ryvita's Goodness Bars are portrayed as the antidote to evil in the brand's new TV ads, breaking on Monday (April 17).
The two-month £2m campaign, which is also in cinemas, is a tongue-in-cheek attempt to show the product's health credentials.
The ad opens in a darkened hall with an evil master consigning his shackled slave to a pit. A cowering wench brings out a platter of Goodness Bars and, after one bite, the master sees the light. He then atones for his wrongdoings by doing the vacuuming, while the wench takes a turn at relaxing.
Marketing director Rob Murray said snack bars had suffered as they were perceived to be high in refined sugar.