With Contrary, all moves that would decrease a stat will now increase the stats, and those that would normally increase a stat will now decrease the stat. This applies also to self inflicted moves such as Close Combat, Charge Beam and Leaf Storm. Baton Passed stat changes are not included.
Contrary doesn't have an effect in the overworld.
Pokémon With This Ability
Related Threadslooking for 6iv contrary serperior or snivy - last post by @ Aug 8, 2015
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Need Snivy with Contrary - last post by @ Dec 28, 2014
I just battled against a Contrary Serperior in the battle maison - last post by @ Jan 25, 2014
Has a Snivy with the Contrary ability ever been released? - last post by @ Nov 16, 2013