Visual oddball tasks are popular methods for studying neural processes involved in attention and perception. This task involves presenting a series of stimuli to a participant, with occasional "target" stimuli mixed in among frequent "non-target" stimuli. Here, the target stimulus is a small red square and the non-target stimulus is a larger red circle. The strenght of this app is that it also depicts the real-time event-related potentials of the participant, generated by averaging the responses to each stimuli whenever is depicted. In addition, it is possible to record "ENTER" keypresses to perform further offline analyses.