Adventure time headcanon:
With the looming threat of a nuclear war, a group of scientists began work on a genetically enhanced baby that could survive the aftermath of radiation. After the first strike, the project was scrapped as the human race began dying off. One young scientist on the project, after seeing her fiancé go crazy, snuck into the lab and hid the baby in a hastily made underground bunker. He was kept in an anti-aging chamber and the scientist hoped it would break long after the war was over, she didn’t want the baby to see this.
Before she left, she put her hat over the boys head. The ends stuck up and he looked like a teddy bear, but at least he would have a peice of the woman who considered herself his mother. She left, and was killed shortly after in a bombing. Her name was Betty