opposite castle- using your opponents pawn for own castle

Have you guys seen any games where the black pawn makes it to the 2nd rank quickly, but the white king just hides behind it? - Or the other way around. 

I recall a Carlsen game where he did that, really early in the game(I forget which one. Maybe one of you knows).

Do you guys or gals have any other examples?

There's a variation in the King's Gambit where this happens pretty early.  White ends up sacrificing three pawns to get black's e-pawn all the way over to h2, where the white king then hides out on h1.  I doubt it's sound, but it's fun.

Yes, I've seen that a lot in games I've seen in the past year, though oddly I never noticed (or saw) it until the past year, for some reason, despite all my years of playing. I don't have any examples handy, but thanks for pointing out that common pattern that I'll start marking when I see it from now on. Usually that situation happens during a kingside pawn storm on the castled king, and usually the (White) king hides at g1 behind the (Black) g-pawn at g2. The reason that reponse caught my attention is that I used to always play g3 as a response to keep that attacking pawn from capturing anything, but if good players are handling that common situation differently, I probably should be, too.