Evokers employed by many of the characters in Persona 3, Persona 3 FES, and Persona 3 Portable to summon the titular entities from within themselves in order to do battle.
Although they can come in a variety of forms, evokers are typically shaped liked a pistol and are similarly operated like one. Summoning a Persona therefore usually requires that the character aim the device at his or her own head and then pull the trigger. Despite the fact that most of them look like guns, however, pulling the trigger of an evoker results in no actual physical damage to the person using it. Nevertheless, their usage in the games in which they have appeared has made them iconic, as the imagery involved in such proceedings can be perceived as being provocative.
As exceptions to the rule, the dog Koromaru is fitted with a special evoker in the form of a collar that he can activate by howling. Additionally, the androids Aigis and Metis do not require evokers, as the their bodies already house such capabilities.
Persona 4 Arena
In Persona 4 Arena, the returning S.E.E.S. members Mitsuru Kirijo and Akihiko Sanada no longer require evokers in order to summon their Personae, as they have gotten over the mental hurdles that required their use. However, both characters still carry them and employ their use in their Instant Kill attacks.