Mean Look is a trapping Normal-type move.
Mean Look prevents the target from switching out or fleeing (including via Teleport). It bypasses accuracy checks to always hit, unless the opponent is in the semi-invulnerable turn of a move such as Dig or Fly. The effect only applies as long as the Pokémon that used it remains in battle.
The affected Pokémon can still switch out via Baton Pass, but in that case, the Pokémon that switches in will now be affected. If a Pokémon traps a target with Mean Look and then switches with Baton Pass the target will no longer be trapped.
Mean Look does not affect Ghost-type Pokémon.
Pokémon that learn Mean Look
By leveling up
Via prior evolution