The Unown are the main antagonists of The Spell of the Unown.
The Unown send Professor Hale into their dimension when he is researching them. Later, Molly Hale releases some Unown from the stone tiles in a box in her house. The Unown, reading Molly's mind, make her wishes come true, including turning Greenfield into crystal and creating Entei to be Molly's new dad. Because Molly also wants a mother, Entei kidnaps Ash's mom.
Eventually, Molly realizes that what she is doing is wrong and she wants to stop, but the power of the Unown is out of control. Entei, with some assistance from Ash's Pikachu and Ash's Charizard, destroys the psychic energy shield around the Unown, sacrificing himself in the process. The Unown are turned back into stone tiles, and Professor Hale is released from the Unown dimension.
None of Unown's moves are known.