Unown [Y]

Once during your turn (before your attack), you may flip a coin. If heads, search your deck for a Psychic Energy card and attach it to 1 of your Pokémon with Unown in its name. Shuffle your deck afterward. This power can be used even if Unown [Y] is Asleep, Confused, or Paralyzed.

You may have up to 4 Basic Pokémon cards in your deck with Unown in their names.

Their shapes look like hieroglyphs on ancient tablets. It is said that the two are somehow related.