Can't believe my suggestion is even getting this amount of attention.......What's more if you use Entertainment after that you'll change another pokemon's ability to Klutz. This essentially means they can't use their item OR ability. But does it revert if they switch? Still, what an interesting idea.
Lopunny@Assault Vest
Klutz
Timid 252 HP / 4 SpD / 252Spd
~ Switcheroo
~ Entertainment
~ Magic Coat/Mirror Coat
~ Last Resort/Rain Dance/Sunny Day/Sandstorm/Fake Tears/Charm/Heal Bell/Copycat
This set is potentially epic. Switcheroo your Vest onto a support pokemon rendering them nigh useless. Afterwards, Entertainment can be used to shut down a second pokemon's ability AND item since Klutz means they can't use it. If the user is likely to carry Taunt or is a Prankster user than simply Megic Coat in their face. Interestingly Lopunny's SpD is a respectable 95 and it's even higher with Assault Vest. This means it can potentially Mirror Coat and actually nab a kill before having to use Switcheroo. This depends on damage calcs. The final slot should be for some support move. Last Resort is situational and her attack is measly but it's 210 BP after STAB so that's SOMEthing. You can run a weather move if enough of your team benefits. Charm or Fake Tears can put the enemy in a real bad position giving you good momentum. Heal Bell to save your team or if you have a lot of Rest users. And Copycat... well, there are lots of possible shenanigans there. She does have Baton Pass but she'd only be able to send Agility and Substitute. Her speed is a good 105 so she can outpace all standard slow support mon no problem and Magic Coat the rest and Pranksters.
Wow... this set is evil.
Also, she doesn't get the boost. Klutz makes her unable to gain the negatives and positives of any held item. Despite that, it's something that can mess up so many leads. Best part is that they can't trick it back onto you.