Speaking of stat shenanigans, I used to use Scarf Gengar with Psych Up + Shadow Ball in early Linked. Dealt with Manaphy and other special attackers that setup. Don't know how effective it would be in today's metagame.
Scarf Gengar into full boosted in sp. atack Manaphy with that combination of moves definitly destroy oponent Set up...
But also means you can't use this setup against any other pokemon, because you will reset boost after next Psych Up. Just because next pokemon did't have boost (maybe expect Download pokemon, but in other case this Psych up remove all boost).
Still better this set than nothing against full boost Manaphy...
But against this pokemon Unaware Clefable can stop this monster (Quagsire didn't want to be hited by that Energy Ball). Scarf Electric/Grass move also is usefull.
More about Copycat (maybe this are mentioned before):
Chansey can use Copycat...
So...
Soft-Boiled + Copycat...
Means Rest wihout sleeping and losing turns (but Natural Cure can go to sleep anyway, so...).
Nightmare of all Sweapers, who really need destroy that wall.
Nobody can now help expect Knock Off+ (STAB) Fighting move - Other combination are weak against his thing especialy on special side. (F.E.A.R. pokemon? are weak in pseudo Parential Bond meta).