"Regeneration?! Oh, come on!"

I rush to the spider with the green aura and stomp its head multiple times.

bloonofsteel Though stunning the spider, this doesn't seem to do any more substantial damage due to its tough chitinous exoskeleton... The missing legs fully regrow, and the spider shakes you off!

mk214ex You manage to kill the other spider with your psionic blasts. You don't know where those spiders even came from: the only door in the room you(and the spiders) came from was shut tight last time you've checked!

blazingwolf It's... completely empty. No symbols on the floor or on the walls, no monsters, no nothing. The only thing that's notable is the cracks in one of the walls, but you doubt any of them have brought enough dynamite to breach this.

Examine the dark maze.

blazingwolf It's... a pretty large maze of walls with a chest in one of the dead ends.

bloonofsteel You put your last bullet in the revolver into the glowing spider's head, and mk214ex Watcher stabs it multiple times at full force just to make sure. The glow disappears, and the dead spider disintegrates into dust, leaving behind a Green Essence Orb.