Chatterskull appears to be based on a folktale "The Laughing Skull," in which the convent of Santo Domingo is haunted by a shaking and laughing skull nestled high on the convent wall. It is said that the hearts of those who hear its laugh will immediately stop. Skulls are a prominent motif in many Central American and Caribbean supernatural stories and artworks.
"A creature of folklore from Dominica. It is a living skull that gives out a piercing laugh. It is said that the hearts of those who hear its laugh will immediately stop."
—Shin Megami Tensei III: Nocturne Compendium
Chatterskull can be encountered in Ginza. As with other members of the Haunt race, the Demi-fiend cannot speak to them unless he either uses the Jive Talk conversation skill if he has it or encounters one in a dazed demon state during the Full Kagutsuchi.
Shin Megami Tensei IMAGINE
"A sentient skull appearing in the folk tales of Dominica. Those who hear its high-pitched laugh are doomed to die. The skull, which holds the brain that governs the senses, is believed to have tremendous spiritual powers. Stories about the power of skulls can be found in cultures throughout the world."
—Shin Megami Tensei IMAGINE Compendium
Chatterskull can be contracted in Ichigaya Camp's silver-level instance and in Ikebukuro at night. It acts as a nightmare variant in the gold-level instance of Ichigaya Camp with a 90% chance to null any physical attack and as a minor field boss on Ueno field.
Shin Megami Tensei: Liberation Dx2
"A sentient skull from Dominican folklore. Those who hear its high-pitched screeching laugh are doomed to have a bone chilling death."