[A Fhaol Bhig]

I'm not hugely experienced at this game but I can vouch for it's effectiveness when used correctly. The main thing is that many people go "lol" and switch to Tyrannitar for example. Which is good and all...except if you've switched in a fighting type, or you alakazam has Focus Blast, etc.

It also helps to turn many 2HKO's into OHKO's.

It's still a niche thing. But it does work.