Levo12

The Aerodactyl is very easy to beat. Any pokémon with the move DESTINY BOND will suffice, regardless of speed or level. Just have it hold one of the following items: Quick Claw (chance that user moves first) Bright Sand (reduces opponent accuracy) Focus Sash (survives one-hit K.O.) Focus Band (chance to survive K.O. move) Failing your attempt doesn't have any consequences, try again and you'll win eventually. I used a level 50 Haunter holding Quick Claw, beat Aerodactyl on 2nd attempt.