The Reverberation is a psychic event that has passed over the Akrotirian Isles multiple times, most recently in Y9888*. To most, the Reverberation manifests as a psychic scream, a discordant chorus of voices shouting into their heads, though others experience it differently. The Reverberation commonly induces a sort of fogginess of the mind, ranging from making it slightly hard to think clearly to rendering an individual entirely comatose. For almost everyone, the Reverberation is painful.
While the individual voices of the Reverberation are rarely distinguishable and recognizable, a few individuals have recorded distinctly hearing the voices of loved ones, either alive or dead. Very rarely, the exact words being spoken can be clearly discerned. Most who experience this go insane.
It is unknown exactly how many times the Reverberation has happened, or its cause. It rarely arrives less than a century after its previous occurrence though not on any discernible or regular pattern. It does not affect the entire Akrotirian Isles at once, but rather seems to travel in a wave, beginning in the south and traveling north, affecting each area for at most a few days before passing.