I’ve had similar things in asking for help in my friendslist when I was still playing WoW, and having a friend come in who was easilly 50% (hyperbole, of course) higher ilevel than anyone else in our party.
That was… Fun 
Although for me as a tank, it was very very hard to keep aggro over his mage.
I don’t even remember exactly where it was. In some raid (LFR I think), but most of our party had dps stats of 10-15K or so, and his was 60K+.