Shuckle @ Leftovers 
Ability: Contrary  
EVs: 252 HP / 252 Def / 4 SpD  
Bold Nature  
IVs: 0 Atk  
- Shield Slam  
- Shell Smash  
- Rest  
- Sleep Talk

Other Options: An actual defensive or webs set (way less passivity thanks to Shield Slam), Shell Bell, 50% Berries, Infestation over Sleep Talk