Welcome to the slightly creepy mushroom World Quest in Genshin Impact's newest area, The Chasm. It's official title is Dimming Mushroom's Call For Help.
This quest will automatically pop up in your quest list when you reach the «Mushroom area,» officially known as the Glowing Narrows. Once you pass by a tall majestic mushroom, a mysterious voice will call out to you. Follow the location highlighted on your map, and you'll find yourself talking to a huge Mushroom «from another land» called Xamaran.
He will ask you to give him some energy, which you can do by using your Lumenstone Adjuvant. After he thanks you, he'll send you on a quest to give his fellow brethren some energy. Go to five marked locations on your map and recharge them with your Adjuvant. It's good to have a fairly leveled-up Adjuvant here--you need a minimum of Level 4--and there are plenty of nearby recharge resources nearby.
The Mushroom King's requests aren't over. He'll then give a Blessings of Wisdom item to you and then task you with following the water flow and finding the «source of foul energy.» Unlike the typical quest, this time, the location isn't marked on your map--so the below image shows where it is if you're struggling to find the source.
You'll know you'll have arrived at the source when Paimon exclaims something along the lines of, «I think that's it!» and you see a blob of corruption. First defeat the enemies guarding the source--hydro, pyro, and electro abyss mages. You'll need three different elements to crack the mages' shields, so I recommend having a diverse elemental overworld team for this. Upon defeating them, you'll receive a Precious Chest.
Cleanse the ooze with your Lumenstone Adjuvant, and then use the Blessing of Wisdom Item
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