I found more data which shows that it has a cry that was reused as the moaning in the background in the old chateau theme. This is reinforced by the fact that a npc refers to pokemon cries in the background of gen 4 themes. No pokemon cries can be heard in other themes. These pokemon also have the pokedex entry "These pokemon are the spirits of children driven to insanity, being with one for too long causes you to become insane"