The Soviet Red Army once trained dogs to destroy enemy tanks. The dogs were trained to associate the underside of tanks with food and were fitted with a 26lb explosive device strapped to their backs. Once the dogs crawled under the tanks, the device was triggered and exploded destroying the tank (and of course the dog). Unfortunately this didn't always work as planned as the dogs were trained using Soviet tanks so were more likely to run under these than the German tanks. As many as 25 German tanks were put out of action this way during the battles for Stalingrad and Kursk.