Obtained: Speak with Ayaha in Fortuna Office in Chapter 6 after defeating the 3 trials and entering the Cosmic Egg.
Per Ayaha’s instruction, head to Daiba Studio and check on Erina Okii, who is hunched over near the map transition. After you speak with Okii, head back to Ayaha to report the news to her.
Since the energy is coming from Cosmic Egg’s Idolasphere, it’s time to head on over there to begin the search. Once inside the Idolasphere, the Mirage will be located on the island to the west. When you approach it, you’ll engage in battle with Fujin (level 60) and Raijin (level 60). Defeat them then head back to Okii in Daiba Studio to check up on her. Afterwards, return to Ayaha to tell her the good news and complete the quest.
Reward: Clap Track and Chakra Pot x3