Possibly the crocodile.
The crocodile could win, but would get badly injured by the ox and the cattlebeast's body.
The black bear would possibly win because it would bite the ox's face. The large ox. It would gore the black bear with its horns.
The polar bear. It would bite the large ox's face.
It depends on the health and size of the two animals, and the position of where are they attacking. If the ox struck the polar bear with its head or knocked its chest, the ox would win the fight. If the polar bear swiped and clawed the ox to death, the ox would be a meal of the polar bear.
The grizzly bear. It will bite the large ox's face.
There are far too many variables in this type of question to get a straight-forward answer.
The ox would win if it is healthy and strong with a gore of the horns on the chest. But is likely that it would get pretty injured.
No matter how you look at it, it is highly likely that the crocodile would win. Why? Because it's so low to the ground and moves quite fast enough that it makes it just about impossible for an ox to flip it over and gore its belly. A crocodile can reach up with its jaws and gut the ox like a fish or break its legs. And this is on land we're talking here, not water. In water, an ox wouldn't even have a chance.
Depending on its health and strength of the ox, an ox is capable of fighting down a bear. A healthy, strong ox can fight off any bear, but would get some injuries from the bear. If the ox charged and gored the bear with its horns before the bear attacked it, the ox would most likely win the fight with the bear. An ox can still gore a bear even as the bear is attacking. All it takes is the right moment and right timing for that ox to let his horns pierce the bear.
Most likely the two lions. The sun bear will not win because the ox will kill the sun bear by hitting it with its sharp horns, and the 2 lions will claw the bear to death. 2 lions are enough to kill a fully-grown ox using their 500 pound body weights, large teeth, and thick claws to bring down the ox. If the lions avoided the ox's sharp horns and attacked on the ox's body top, the lions can win such a fight.
A lion because it can defend it self better then an ox and bear. The black bear will not win when the lion can kill it with a weight advantage and teeth, and also the ox can knock its chest with its thick head. This leaves the ox and the lion fighting. A lion has sharp claws and sharp teeth, while an ox has a thick, strong body, sharp horns, strong head, and large hooves. If the lion charged at the ox, the ox can hit it with its horns and kill it.
Lions, especially if they are females from the same pride. The grizzly bear can defeat and kill the ox if it avoided its horns and head, but the lions will get it after the grizzly bear gets injury by the ox's body strength. If the grizzly bear attacked the 4 lions, the grizzly bear will have a chance to win because its big claws can kill 2 lions if it was strong enough to. After the lions get killed, the grizzly bear might get injured, and the ox can kill it with ease.