Himself, or in a fight?

Towards the end of Van Gogh's life, he was sat in his studio surrounded by many of his unsold paintings.In fact, during his life he only sold one, and that was to an art gallery owner. Those paintings each sold for many millions after his tragic death. In fact he gave one to his doctor, who didn't like it so used it to repair his chicken coup. It was worth $50m in 2016.

It's well known he lost his ear, and most believe he did it to himself. However, this story has taken a few twists down the years and the absolute truth still is not certain. His friend Gauguin was planning to leave, and as Wikipedia reports:

Van Gogh followed when Gauguin left the house for a walk, and "rushed towards me, an open razor in his hand". This account is uncorroborated; Gauguin was almost certainly absent from the Yellow House that night, most likely in a hotel.

Gave ear to a girl

New research from 2016 suggests Vincent gave his ear to a maid working in a local brothel, who was not a prostitute herself.

Doctor

The doctors report shows almost the whole ear was removed:

Did Vincent Van Gogh really commit suicide?

Too further add to the mystery, it has been claimed his reported death by his own hands with a shotgun might not be accurate, and he could have in fact been murdered.