So i had a battle with some one before and they used a method i had never seen before.
it was a long fight but in short this is what he did.
1)Shedninja (with Focus Sash) use mimic to mimic his own skill swap.
2)He swaped out his skill swap (think it was an epsion) for spiritomb
3)Skill swaped wongergaurd to spiritomb
4) Used will-o-wisp and rest (dont know his other moves he dident use them)
The match ended with him leaving because i think he knew he wasn't going to win with my lapras water absorb kingdra and ludicolio with surf and zapdos with pressure so in the end he would just run out of pp.
just thought i mentioned it because i hadn't seen it before and it seemed to be a legit way to skill swap wondergaurd
(just for the record all his pokemon seemed to be hacked they were all shiny all hit very hard or had a lot of hp and were all very fast without tailwind)