Recover. Recover is good for a Pokemon with stat-raising moves, and is reliable, healing the same amount each time. Though you dont have any dark type coverage, you can use Reflect and switch out to give bulk to your team to defeat the dark type opponent, and dont be afraid to switch back to Beheeyem, as it can always heal with Recover. Talking about tanks and walls, Beheeyem with Recover is a tank that can resist against walls that don't have toxic. I hope this helps! -Jellohamster
