Arena Trap (ability)

Arena Trap is an Ability introduced in Generation III.

In battle
Arena Trap prevents all grounded adjacent opponents from fleeing (including Teleport) or switching out as long as the user remains in battle.

Using Baton Pass, U-turn, Volt Switch, or Parting Shot will still cause the Pokémon to switch out. Holding a Shed Shell allows the Pokémon to switch out, but not flee or Teleport. Having the Ability Run Away or holding a Smoke Ball allows the Pokémon to flee or Teleport, but not switch.

If a wild Pokémon has Arena Trap and the player's Pokémon faints, if the player attempts to flee instead of sending out another Pokémon, they are unaffected by Arena Trap. Arena Trap does not affect allies.

Outside of battle
From Pokémon Emerald onwards, if a Pokémon with Arena Trap is in the first place in the party (even if fainted), the wild Pokémon encounter rate of all Pokémon is doubled. It shares this trait with Illuminate and Swarm.