SCP-523 does not have a consistent physical form, nor does it have any distinguishing marks by which it can be identified. It does however emit a low-frequency telepathic signal which persons capable of detecting describe as "a dull ringing sound." This signal can be used to locate SCP-523 if it "escapes." This frequency is also assumed to be the source of SCP-523's ability to short out electronic recording devices such as video cameras and blank out camera film.