While doing the stomp boss, at regular intervals he becomes invulernable and you need to get the rocks and activate them to prevent him from healing. Sometimes he puts debris in the way though making this task impossible.
You can prevent this from being a problem by putting a gatestone next to the lodestones then teleporting to them if there is an obstruction. If you're soloing this only improves your chances. If you're 2 manning or more though, this guarantees that you'll always be able to activate the stones.
I'll update this thread with pictures next time i get him as a boss, it's fairly self explanatory though.
Edited by Protoman1600, 26 April 2010 - 04:17 PM.