I was running naxx the other day and I saw my shadow priest friend go right through the blobs without dying.
The trick is to use a heavy -damage modifier ability, shadow priests have dispersion, which allows them to take much less damage, so that they can pretty much auto-run through all the slimes and still not die
Of course this also works with any other class with heavy -damage modifiers such as warriors with shield wall, or perhaps pain supression though i'm not sure if that is enough -damage %.