The large bear-like man who shelters Bilbo’s company is Beorn.
Beorn is a “skin-changer,” a person who can assume the form of a great bear. In The Hobbit, he lives in a large wooden house between the Misty Mountains and Mirkwood, keeping horses, sheep, dogs, and other animals. Gandalf introduces the company gradually because Beorn distrusts strangers and has little love for Dwarves.
After the Goblins and Wargs pursue the travellers, Beorn confirms their story by capturing and questioning enemies. He then gives the company food, shelter, ponies, and advice for crossing Mirkwood. His hospitality is especially important because the group is exhausted and about to enter one of the most dangerous regions of their journey.
A common mix-up is confusing Beorn with a bear who merely accompanies the company. Beorn is a man who changes shape, and his bear form later becomes decisive in the Battle of Five Armies. He attacks the Goblin forces and kills Bolg, helping turn the battle in favour of the defenders of Erebor.