Something quirky to do in Katowice/Kraków in October

Hej, drużyno orłów!

This October, my crew and I (4 heavy metal fans 🤘) are heading to Katowice! We've already got our Auschwitz tour planned and we're attending Helloween+Beast in black concert, but we're looking for quirky, offbeat, and metalhead-approved things to do while we're there.

We're up for anything:
Dive bars or underground music spots?
Cool, eerie castles or ruins nearby?
A quick train to Kraków or a hidden gem in a nearby town?
Something industrial and gritty to explore?

Dzięki!

EDIT: thank you for the helpful comments!