I've always been intrigued with kangaroos. They just seem like such a peculiar animal that is so specially/purposefully designed. I always joke with our deer lease rancher, who sometimes goes to exotic animal auctions, that I'm going to start a "go fund me" for us, so he can buy us a kangaroo. I always envision us sitting on the porch like the two guys in the movie "Secondhand Lions".
I've watched some videos of them fighting and they seem pretty smart. One tactic they take with dogs, is to get them into the water, where the kangaroo will then drown them by holding them under.
On one of the hunting forums I frequent, a member there posted photo's of them having truck bed loads of kangaroos. I guess they hunt them for pest control, but also for the tail meat.
Of course, the toughest animal is a honey badger. They're the Chuck Norris of the animal kingdom.