A truly original and weird module, Earthshaker! is kind of a Kaiju-style adventure set in the D&D world. Being designed for the Companion Set rules, this is for really high level player (18-20), which means that the enemies have to be equally colossal. And in this case they certainly are.

Here your party is given responsibility for a Dominon (although you can and should maybe use one of your character’s own dominions if they have them) and into this area comes a travelling fair bringing with them an enormous metal Steam powered robot, the titular Earthshaker! The colossus is passive at the start but a gang of evil doers plans on taking it over and using it for their nefarious ends and you have to stop that from happening.

This module also introduced Tinker Gnomes to Mystara (then known as the Known World), technologically advanced and quirky little guys which seem to take inspiration from the recently introduced Dragonlance gnomes of Mount Nevermind (which are even quirkier!), this is the prototype of gnome which would be prevalent down to our days, look for example to the gnomes of the Warcraft universe and you can see them coming directly from these little tinkers.