I used the Rune III clickie on webtools/items.php?id=11038, and it worked...to good.
On my bot, it would absorb limitless amounts of damage it seemed like, then I zoned, rebuffed him with it, and it would drop in one shot from an Orc Pawn. My shaman and my zerker both had it on, and i had the whole throne room in CB on me and wasnt taking a lick of damage. I rebuffed midfight with it as it was about to expire and it did the same thing as it did to my bot, dropped in one shot.
I havn't been able to reproduce this, but i'll try and tell you what I come up with.