In AI: The Somnium Files, during the chapter PSYNCIN' IN THE SUSTaiN, Aiba can interact with a wall of signatures and examine 3 specific autographs marked as "Left," "Middle," or "Right." Selecting these options give the following:

• Left - For 99 seconds, an autograph from someone named "Hongo" is shown. Aiba notes that she can't "picture the face" and a jingle plays.
• Middle - For 78 seconds, an autograph from someone named "Enoshima" is shown, featuring drawings of a black bear and a white bear. Aiba remarks that she "hopes" to find out who that is, and a second jingle plays.
• Right - For 12 seconds, an autograph from someone named "Mikimoto" is shown. Aiba describes him as "a photographer with some sort of beard like a mountain man" and a third jingle plays.

All 3 of these options are references to the games Zero Escape: Nine Hours, Nine Persons, Nine Doors, Danganronpa: Trigger Happy Havoc, and Kamaitachi no Yoru (renamed Banshee's Last Cry in the iOS English release). These games were all developed by Chunsoft or Spike (before the merger), and the jingles used are audio themes used in each game. These specific references are about Spoiler:the respective villains of each of those games, and doing all 3 of these options unlocks the achievement "Crazy Awful Customers."

• 999 - Spoiler:References Gentaro Hongou, nicknamed Ace, the antagonist of the First Nonary Game. He has prosopagnosia, a disorder that prevents someone from recognizing faces. The 99 seconds references the title of the game, shortened to 999.
• Danganronpa - Spoiler:References Junko Enoshima, the mastermind of the "Killing School Life" death game who controls Monokuma. She holds the title "Ultimate Despair," and her goal is to abolish "Hope." The 78 seconds references her class at Hope's Peak Academy, Class 78.
• KnY/BLC - Spoiler:References Yosuke Mikimoto (named Jonas Faberge in the iOS English release), the culprit of the murders at the skiing lodge. His disguise involves wearing a fake beard to appear as a mountaineering photographer. The 12 seconds references the 12 people staying at the skiing lodge, or perhaps the 12 potential victims that Mikimoto can kill in bad endings.