So I avoided this quest for a bit as I did all the main quests, but I finally decided to do it and it was so... scary that I had to make this thread. You can find the quest at the doorway to the Greymoor caverns in Arkthzand here...
You end up following the tale of a Nord who got himself trapped down here and he did his best to survive. Sadly he needed food and he decided to eat the Blackreach mushrooms... but amazingly he didn't die.... immediately. Like the Cordyceps fungus it ended up worming its way into his mind and he ended up going insane and having a desire to "root" himself so he could grow.
He ended up finding the perfect spot and his fate.... is rather terrifying to be honest...
So.... don't eat the Blackreach mushrooms!!!
PC NA - Ceyanna Ashton - Breton Vampire MagDK