I had a staffordshire bull terrier (fairly small but stocky as fuck breed) that teamed up with the neighbours staffy and went on a mini massacre in a wild life sanctuary that was just down the road, they took out a couple of kangaroos which is pretty impressive since these dogs were probably not even a quarter of the height of the roos, the owner of the sanctuary drove round to everyone near by with the dead roos in his boot screaming his head off at everyone haha.
It would take a pretty mental dog to take down a red kangaroo though. them fuckers are like 2 metres tall