Techniques are disclosed that involve mobile augmented reality (MAR) applications in which users (e.g., players) may experience augmented reality (e.g., altered video or audio based on a real environment). Such augmented reality may include various alterations. For example, particular objects may be altered to appear differently. Such alterations may be based on stored profiles and/or user selections. Further features may also be employed. For example, in embodiments, characters and/or other objects may be sent (or caused to appear) to other users in other locations. Also, a user may leave a character at another location and receive an alert when another user/player encounters this character. Also, characteristics of output audio may be affected based on events of the MAR application.