Down Below by Leonora Carrington:
I was studying the matter closely, hanging bat-wise from the bars with my feet, my back turned to the room, and I was examining the bars on all sides, from all angles, when someone jumped on me. Falling miraculously back on my feet, I found myself face to face with an individual with the expression and aspect of a mongrel dog. I learned later that he was a congenital idiot who boarded at Dr. Morales’s. Being a charity case, he served as a watchdog at Villa Covadonga, a pavilion for the dangerously and incurably insane named after Don Mariano’s daughter who died. I realised that any discussion with such a creature was perfectly useless. I therefore took prompt measures to annihilate him. Frau Asegurado watched the battle from the vantage point of an armchair.
I was superior to my adversary in strength, willpower, and strategy. The idiot ran away weeping, covered with blood and terribly punished with scratches. I was told later that he would have submitted to death rather than come near me after that fight.