Phantasmal Gates are arches made of tree trunks with musical notes spilling out in the middle. When you play an Aranara’s tune in front of them, the music notes will turn into a gate, and crossing it will prompt a Challenge to start. You can find these Phantasmal Gates all over Sumeru’s rainforest area, and will first encounter them in Aranyaka Part II - Dream Nursery.
You need to complete the first World Quest in the series called The World of Aranara to obtain a Gadget called the Vintage Lyre, which is necessary to play a tune to unlock these Phantasmal Gates. Additionally, make sure to bring a character that can apply Electro without cooldown (Yae Miko, Lisa) as they’re necessary to make this Challenge easier.
How to solve Phantasmal Gate Dendro music note puzzles in Genshin Impact
When you first encounter a strange arch with music notes, use the Vintage Lyre and play Arana's song, the Rhythm of the Great Dream. To do so, use the first line of the music score and play the following notes in this exact order: fa > mi > so > fa > do.
Once that’s done, the music notes will turn into a gate. Cross the gate to begin the Trial of the Phantasmal Gate, a Challenge that requires you to collect Phantasmal Seeds. These are green Particles scattered all over the Challenge area, which is highlighted yellow in the mini-map. It’s very important that you stay within the Challenge area, or it will fail.
You have about a minute and 30 seconds to complete the Challenge, but collecting a Phantasmal Seed will replenish the time limit. As you search for the Particles, you will encounter purple flowers called Dream Flowers. Attack them using Electro to prompt yellow lights that spill vertically into the sky to show up, indicating the locations of the rest of the Phantasmal Seeds. However, the yellow lights are not permanent. If you idle for too long, they will disappear, and you need to activate another Dream Flower for them to show up again.
Along the way, annoying fungi will try to attack you. Be careful of their spore-shooting attacks, as being hit by one of these will remove about 30 seconds from your Challenge time. Shields will not protect you from these attacks, but they’re accompanied by red highlights on the ground, so they’re fairly easy to dodge.
The Phantasmal Seeds are usually scattered in a circular path, so the final one should lead you back to the Phantasmal Gate. Once you’ve collected all Seeds, interact with the Phantasmal Gate to complete the Challenge and get a reward.
Check out our guide on How to unlock & switch between real & dream Vanarana in Sumeru in Genshin Impact to explore the area's two forms.