The Unown sent Professor Hale into their dimension when he was conducting research on them inside a temple. Later, Molly Hale released some Unown from the stone tiles hidden in a box in her house. The Unown, reading Molly's mind, made her wishes come true, including turning Greenfield into crystal and creating Entei to be Molly's new father. Because Molly also wanted a mother, Entei kidnapped Ash's mom.
Eventually, Molly realized that what she was doing was wrong and she wanted to stop. However, the power of the Unown had spiraled out of control. As a result, Entei destroyed a psychic energy shield that formed around the Unown, sacrificing himself in the process. The Unown were subsequently turned back into stone tiles, and Professor Hale was released from the Unown Dimension.
Personality and characteristics
The Unown are creatures that do not want to be disturbed as shown when they took Professor Hale into their dimension. They have the power to make someone's wish come true without the person telling them so as evidenced with Molly Hale, but at the cost of their own energy force.