Is it normal my neice is a sadist?

My neice is five years old and laughs at her mom when she accidentally stubs her toe or falls and hurts herself.

She became really giddy one time when I fell down the stairs and another time when I accidentally cut myself while slicing onions.

She laughs hysterically even when someone cries from emotional pain. Because of this, she began bullying her cousins until they cry and laughing about it. We punish her a lot for this but it does nothing.

Recently, I watched her and she hit me in the head with a wooden block and laughed when I got upset about it. The whole day was hell from that point. Pinching, biting, hair pulling and all. I never want to watch her again.

Is it normal for a child to be evil like this?