The Mountain View, Calif.-based search engine said the format is in test run and that it is designed for customers of Google's AdSense for Content product only.
Google also said it plans to expand Adsense with new formats in the future, including an expansion to include 21 languages.
The animated ads will follow the same editorial rules and 50KB size limit imposed on image ads. Adsense customers display text and image ads on their sites that are targeted according to a given page's content.
Advertisers under Adsense win placement based on price set in an online auction, and then pay each time a potential customer clicks on their ad.