I find this 'Team' incredibly annoying, so I'll throw in my two cents.
First of all I do not consider this merely an evolution of the parafusion strategy, this is a different thing altogether. How? Two primary reasons: the first is that there are now multiple entry hazards (as opposed to just spikes in gen 2). The second is that unlike previous generations, Foul Play exists as well as Prankster.
Prankster is huge for this team because it allows a bypass of speed, paralysis or not. Normally when detailing with Parafusion or, similarly, something like Serene grace abuse you can switch in to something FASTER with lots of firepower and then this would counter it.
EG: Serene grace jirachi paralyzes my breloom, I know it will iron head me to death so I switch to scarf volcarona or something, and thus threaten it out. Or Fire Blast it, either way it's out of my hair for a while.
Prankster negates this completely, since no matter how fast you are prankster is still faster. Combine this with swagger and nothing can escape being Swaggered unless you get lucky and it misses. Even then, you'd have to OHKO the user (which is a difficult feat thanks to sub) and then dealing with the same thing again since that's how these teams work.
So yes, in order to counter this I believe the previous statements about how you have to run something like espeon or thunderus, or even whimsicott. I don't believe I have to give any reasons for how this severely limits teambuilding, or in some cases forces you to use non OU material, which only has its merits defeating swagplay and loses to anything standard in OU. The example of Numel comes to mind for this last point.
So now here is the question: how does one defeat this team without resorting to tactics that fail against every other standard team? I actually have the answer to this one, but it's not a very good answer: You spam attacking moves from the get go. See a Klefki? Spam earthquake. Do not switch, do not use any other move, just earthquake until it dies.
As someone pointed out earlier, switching is the worst thing you can do against these teams. They will merely spam swagger again and again, and your switching racks up entry hazard damage. You can win against these teams by merely NOT switching and adopt straight up offense.
The problem is, this strategy works only 50% of the time due to swagger. With the attack boosts, you can either get rid of a klefki with earthquake or hurt yourself while it fires up a sub and then its back to square one. But what about things like Thunderus, which also have prankster but can carry taunt? Essentially the same thing: Obviously these trolls are going to run max speed on all these pranksters for this reason. If you send out your thunderus against another thunderus, you have a 50/50 chance due to the speed tie of setting up your taunt. If you can't, refer to the aforementioned consequences.
Thus, if you wish to try and taunt them, you must run taunt Whimsicott of all things. So... do that if you want I guess. Maybe it'll work against the standard teams too?
What about Magic Bounce Xatu and Espeon? These could potentially work. A foresee a baton pass/sub set with espeon being a viable counter to these teams, but you cannot use setup moves like CM or you run into the ditto that most of these teams have, then its just GG sweep. In addition these things are somewhat frail, so I suspect in a game where you run into thunderus on the opposing team, they (especially xatu) would probably lose. That, or force you to keep switching (racking up entry hazard damage) proceeding to swagger until your counter is worn out.
Thus, you have to run your espeon to counter both thunderus and klefki at the same time, since one can potentially do a lot of damage to your counter while the other can use its incredible defensive typing to wall until the supereffective foul play defeats it. I do not believe espeon can counter these two at once, but if anyone can prove me wrong post that set and I'll consider using it.
So until someone finds and espeon that can counter Thunderus, Klefki, but does not set up (due to ditto), we will have to make do with what I believe to be the only hard counter to this team: Whimsicott, since it is the fastest prankster available. This will work until someone notices this threat and puts prankster whimsicott onto thier team.
If you don't feel like running that, then spam HO. You have a ~50% chance to win in this case.
Lastly, I'd love to go over all the other examples (rotom W, ground types etc) but my fingers are too tired from the material I have already posted, and I have class in five minutes so there's that.
In conclusion, these teams rely solely on luck to win, even in the case where the opponent is smart enough to not switch. This would not be a problem is it was one Pokemon, and could even be considered a viable strategy, but instead it is a 6 membered team composed of utilizing luck to win. There are some counters, but these are not hard counters (save maybe whimsicott and subpass espeon) and thus there is not true way I can think of to combat this.
Please give me your thoughts and comments. This needs to be dealt with, because I do not want a metagame based upon a coin flip.
Small edit: I did not mention t wave because I believe that is easier to deal with than swagger; just run a ground or electric type. Also, if anyone can post the calcs of standard kelfki foul play vs standard espeon and xatu, that would be appreciable.
