Metaphysical App

A smartphone app that has a supernatural function that can affect on the world compared to mundane apps. It's usually found in Urban Fantasy where it is a major part of the plot or just another aspect of the setting.

Not to be confused with any sort of killers but more so dealing with the term, killer app and the slang word 'killer'.

Anime and Manga

 * Darwin's Game (as pictured above) is the titular game that gives participants a Sigil, which is a power randomly bestowed to each user. The players in the game can have players battle to the death. There also events where players are teleported to different areas in order to play, such as clans gaining territory and defending it for 30 minutes.
 * Ingress The Animation is the Animated Adaptation of the same mobile phone game. The app is a cover for the two factions of the Enlightened and Resistance to wage their battle through the public. It is used to collect XM or 'eXotic Matter' that comes from another dimension. People called Sensitives have abilities that can be amplified by it, especially in a Control Field of their aligned faction. They can be, however, dampened or negated if they are near an enemy Portal and Control Field.
 * Real Account has the titular app which is also called Re-aca is a popular social media application. It was a normal app until it was used where people's minds are transported to a virtual space, and their real bodies lay unconscious. They are then forced to participate in a game that depends on the number of followers they may have. If the participant dies during the game, the person dies in the real world along with the followers. They can also die if their follower count falls to zero, but then the followers won't die.
 * UQ Holder have magic apps in the setting where magic and technology have advanced to the point that people can use a program without the need of training and talent.
 * The Yuusha System App from Yuki Yuna is a Hero is used by the Hero Club members. The app has different features a chat function, transfer a user to the Jukai, a radar to locate the heroes and Vertex in the other world, giving superhuman abilities, Fairies that can give weapons and other powers to the user, and seal a Vertex in order to defeat it.
 * The smartphone app which can hypnotize people is a common device in Hentai manga.

Video Games

 * Devil Survivor 2 has the Demon Summoning App where a person can make a contract and summon demons while also be able to fuse them. The analysis of the app by JPs states it simplifies the rituals. There is also Nicaea β ver. which gives a video of a user's death along with videos of friends.
 * Shin Megami Tensei IV and Apocalypse has the people of Tokyo use smartphones with the Demon Summoning Program loaded on it. It was released before the Ceiling in Tokyo went up through the internet, but no one knew why it was created and distributed. A phone equipped with the program is usually awarded to people who become an official Hunter.
 * The Metaverse Navigator or MetaNav from Persona 5 is an app given to him by Igor that allows the protagonist to go to the Metaverse. It can also be used by others that the protagonist allies. To use the application, one would need a keyword(s) to enter the Metaverse.
 * Tokyo Afterschool Summoners has the app called SUMMONS, which gives a user that power of Summoning. Summoning is the act of an entity being brought to a world from another through a pact. It can also grant an item called a Sacred Artifact that have a unique power called a Rule. The App can also be used for communication, track other users, and make a guild with other app users. There are also App Battle where users fight each other in a Battle Zone. These Battle Zones allow for the use of Sacred Artifact's Rule. Once the Battle Zone is terminated through forfeits, loss, or turning off the app, any damages made from the battle within the area are undone.

Web Comics

 * In DICE: The Cube That Changes Everything, Dicers gain an app that allows them to allocate their Dice Points and get notifications on quests where they can get more Dice. There is also a store that can be Dice Point to buy items like potions, temporary stat boosts, or even items that can affect an area.
 * Emily (or Emile in other translations) from Tower of God is an intelligent chatting bot that was made by the Acorn Workshop.
 * The Great Labyrinth Era from The Gamer is an app that acts like an average mobile game but when a person falls asleep, they are transported spiritually to the actual labyrinth. In the location, they are in a dungeon-like area where they can increase their level, stats, and gain items by defeating the monsters inside.