Found a mine, led to the altar with a petrified eye. Feeling curious, I examined the pedestal where it should summon lots of dark wyrms. So I’m hearing crashes everywhere, but I reckon the dark wyrms have no idea where I am so I waited for an hour.
And the walls collapsed, and around 50 dark wyrms came out.
…it should have been intimidating, but the dark wyrms seemed to have the detection abilities of a concussed duck who got hit by a flashbang. I pretty much just hovered at the edge of them and killed them all.