DM Mike’s bronze skeleton is a cool idea. Gives a bit of standard cannon fodder just enough of a tweak to make it more of a threat at low levels. It is so easy to boost monsters for just about any level, but takes a bit more imagination and effort to truly alter a monster to make it different and challenging. Bravo.
I’ve done something similar with liches in one of my ancient and lost empires. The wizard-kings would be gilded after death (coated in gold), to return as a “golden lich.” This improved their AC by a little, but was mostly a sign of prestige. In any case, it would make the players pause at the start of the encounter as they tried to figure out what was going on. As a DM, I like to connect with the players behind the PCs.
Has DM Glen been watching The Slayers anime series? Love live the fighting fish.
I always saw Hollow World as an excuse to trot out the few ancient cultures Mystara failed to exploit on the surface. I don’t mind ignoring printed material in favor of my own concepts. I do bristle a bit at paying for hundreds of pages I don’t want.