Cofagrigus @ Rocky Helmet
Ability: Mummy
EVs: 252 HP / 252 Def / 4 SpA
Bold Nature
IVs: 0 Spe
- Pain Split
- Will-O-Wisp
- Psychic / Hex
- Trick Room / Substitute / Disable
This is the best counter i could think of. A ghost pokemon you say? Know that mega lopunny has scrappy? I do, but cofagrigus has mummy, wich means that if cofagrigus is hit by a contact move - and lopunny only uses contact moves - the attacking pokemon get its ability deleted and gets mummy instead. This means lopunnys normal and fighting moves wont work anymore against cofagrigus.
Apart from that he has a high 145 defense stat but a not so high hp stat in 58. Pain split works very well with that low hp stat, because it combines the hp of both pokemon and gives half to both. Cofagrigus often has a lower hp stat then his opponent so this means he can get hp back and lowers hp of the opponent in one move.
Will-o-wisp is for crippling lopunny (and other attackers) and psychic is for dealing super effective damage to lopunny but with all the passive damage lopunny will get (rocky helmet, burn and pain split) it isnt even necessary. Hex turns in a 130 base attack ghost move if the opponent is statused so works with will-o-wisp well.
For the last slot you have a ton of options, trick room is nice because cofagrigus has a low speed stat, substitute gives cofagrigus a status immunity and more longevity. Disable can also be very nice for lopunnys ice punch so it completely makes lopunny useless against him (or a kanghaskans earthquake)
252 Atk Mega Lopunny High Jump Kick vs. 252 HP / 252+ Def Cofagrigus: 64-76 (38.7 - 46%) -- guaranteed 3HKO
Most lopunnys are jolly , 94 % , but he can live the 2hko of adamant too (altough he doesnt need to thanks to mummy)
252+ Atk Mega Lopunny High Jump Kick vs. 252 HP / 252+ Def Cofagrigus: 135-159 (42.1 - 49.6%) -- guaranteed 3HKO
Ice punch from adamant does barely do 20% damage
252+ Atk Mega Lopunny Ice Punch vs. 252 HP / 252+ Def Cofagrigus: 28-33 (16.9 - 20%) -- possible 5HKO