Ive been thinking about this, and want to see if it’s possible. If youve seen my Team Discussion post listing my team, I have a Serperior with the ability Overgrowth. I was wondering if I could use an Ability Capsule to change my Serperiors ability to Contrary? I know its a long shot but if I could get Contrary on serperior, I could reteach it Leaf Storm and get a 1.5 Sp Atk boost every time I use it.
No, ability capsule won’t work because because Contrary is the hidden ability. You can only get hidden abilities through the friend safari. Furthermore, leaf storm gets you a x2 special attack raise if you have Contrary
Ah, Okay. Thanks for the info anyways 
I would definitely advise taking time and effort to get a Servine with Contrary from the Friend Safari (just lead with a Pokemon that has Intimidate). IMO Contrary is one of the strongest Abilities in the game, and I get some good use out of it in my OU team (not to mention it’s even better for regular gameplay, since the AI will never figure out that Sand Attack/Fake Tears/etc. is a bad idea).