Allright! Cofagrigus is just awasome.
Relaxed nature (+Def -Speed), EVs 252 Defense, 252 HP, 4 in Sp.Atk, Item leftovers and of course the awasome ability Mummy.
-Shadow Ball Good STAB move .
-Hidden Power Fighting this covers Dark-, Normal- and Steel-types that shadow ball isn't very effective against and provides perfect at least neutral coverag alonside Shadow Ball
-Calm mind Raises the Coffin's Sp.Def and Sp.Atk powering up Shadow ball and Hidden Power Fighting In addition, makes Coffin bulkier, Giving it good Special stats as well as HP and Def. So with max HP, max Defense and Calm Mind, this Coffin is very bulky.
-Trick Room, this takes advantage of the low speed, also makes him get a free calm mind before the opponent attacks.
Some of the Coffin's partners should preferably benefit from Trick Room as well.