In March 2014 an image of a flaming back-pack carrying cat was making the rounds on the Internet. Here is my take on the story:
A German illustrated manuscript treatise on munitions and explosive devices entitled Feuer Buech, produced in 1584 by Franz Helm, contains, among descriptions of more conventional devices, an image of a cat and bird wearing flaming backpacks to attack a city under siege. This image appears on leaf 137 recto. Considering the notorious independence of cats, and the very limited carrying capacity of birds in flight, it is extremely doubtful that using a cat or a bird to set a city or building on fire was ever successfully employed. Most of the other devices in the manuscript seem more practical.
The manuscript is preserved at the University of Pennsylvania Medieval & Renaissance Manuscripts Collection Codex MS 109. It is also part of the Edgar Fahs Smith collection on the history of chemistry. In March 2014 a digital facsimile of the entire manuscript was available at this link.
The image was printed on page 48 of Armamentarium principale oder Kriegsmunition und Artillerey-Buch ... Beneben einen Bericht der Wagenburg, issued in Franckfurt by Johann Ammon in 1625.