Unown are floating, flat, eye-shaped Pokémon with appendages that make them resemble letters. They are black all over. All alphabetic Unown have fully open eyes while the two punctuation Unown have half-closed eyes.
This Pokémon is genderless.
Unown's only known move in battle is the enigmatic Hidden Power.
In the anime, they are capable of reading the thoughts of other lifeforms. Great numbers of them are capable of warping reality to suit the dreams and wishes of whoever they read the thoughts of and is in control of the Unown. However, they can only do this when more Unown are present, so it could be a shared effort rather than an ability unique to each Unown.
Unown can make telepathic contact with humans (as well as many other creatures). Unown have a timidness that makes them rarely venture outside of their dimension. They tend to stick to walls or orbit other Unown when in a group.
Unown live in their own dimension.
When they move to the Pokémon world, Unown seem to prefer to make their habitat in ancient ruins stuck to the walls, appearing only in the Ruins of Alph in Johto.
This Pokémon was unavailable prior to Generation I.