I say twin because the portable space heater does have a sister that is much calmer, cooler, and much more delicate.
She is the portable air conditioner.
The portable space heater came to us at first making all humankind feel comfortable during the cooler days. The days that the portable air conditioner unit could take a break. He would slide right on in on his four wheels and blow the chilly factor off your skin. Making you feel that warm air like you were in the middle of summer. He did his job and did it very well. Some people even preferred him over his twin sister. Then one day something happened and no one really know what happened. He started to lose it and started to go mad. I think some speculate that he didn’t like that his twin sister was being used at times when he should be used. His jealousy started to build inside to the point that he didn’t want to help people anymore, but make their lives terrible. Once a hero, became a villain that no one wanted to encounter. Before he turned evil, stores around the nation had toys for kids praising him and the at-home comfort he brought. Much like his sister, replicas of him were created but they didn’t have the brain that he had. He was a one of a kind and thankfully he wasn’t duplicated. Lots of people around the world have some sort of version of him but they don’t have to worry about their portable space heaters turning on them.