The “Rusty Cave” is rumored by everyone around Goldvale to be the habitat of a rust monster. Given that everyone frets about their metal items rusting in an encounter with one, the cave does not get many visitors.1)
It turns out however that this cave is not the home to any rust monsters. Instead it is a gold vault once owned by gnomes. Gnomes who left mechanical and magical traps behind. The Rusty Cave hides additional lore. Gnomish in nature, with a huge amount of gold sitting around and possibly other surprises for some future time.
In this campaign eventually Skip goes to the Rusty Cave believing there to be treasure, for which he is very correct, but he gets trapped in a vault where the gold is acting like quicksand.
The Party of Jules, Eyrun, Urist & Alimir head to the Rusty Cave when they are informed by none other than Wyrd Uncle Lugo that Skip has not been seen in many days after partaking of this treasure hunt. There they stumble into the gold vault only to have a portcullis trap them inside and a gnomish mechanical construct with spellcaster abilities suddenly attack them to defend the vault. They find Skip still alive but things get worse for everyone, very quickly.