Slow Pokémon move first for 5 turns.
Trick Room is a Psychic-type status move that reverses the turn order for five turns, causing slower Pokémon to move before faster ones. In Polished Crystal, Trick Room can be learned by various Psychic-type Pokémon, providing them with a strategic option to control the flow of battle by altering speed dynamics and giving an advantage to typically slower team members.
This is a Move Tutor move. TThe location page may have more information on how to obtain it.