1 story verifying that heat rocks can kill. While I have never kept an eastern hognose I have kept westerns and I have also seen westerns and mexicans basking in the field. A discussion I had with a friend confirmed what I have personally witnessed - heterdon nasicus will bask on rocks/ground where the surface temp of the basking site is in the neighborhood of 100 degrees.
So in order for your eastern to have literally gotten fried, that heat rock must have been incredibly, dangerously, hot.
Still need more ghastly tales of gross bodily harm before they even make a tiny dent into what I've personally seen with other heating sources.
Again, don't get me wrong, I'm not a user or a fan of the heat rock.
FWIW the one I bought out of curiosity peaked at 101 degrees.
The surface of my radiant heat panels get higher than that. Still not enough to cook a snake. When I owned monitors the surface temps they used to bask at were about 40 degrees higher or more.
Got a couple of e-mails from people who have used their heat guns on heat rocks and haven't seen one yet hot enough to cook a reptile.
I once had a young pseustes that managed to find a way (in a Vision cage) to lodge herself on top of a Pro-Products radiant heat panel.
She'd spend a lot of time in there. Sometimes the temp on the top side of that panel registered over 100 degrees and she never got a burn.
Keep those horror stories coming.