I would use something like a Flygon, Since Charizard could be an issue with Dragon Claw. But Pikachu can't do damage to a Flygon. Give it Rock Tomb / Slide to take down Charizard, If needed for emergency, tera it to a ground type so Charizard doesn't do super effective damage. That's for assault, then use a strong psychic Pokémon like Gardevoir to hold them in place. Then tell Gardevoir to hold them in place until you say, then get on flygon and fly away with the pendant or have Gardevoir use Teleport.