Lemures

The lemures were the restless, potentially malevolent spirits of the Roman dead — the counterpart to the Lares, who were benevolent household ancestors. They were believed to walk at night during the Lemuria festival in May. The festival's founding was attributed to Romulus, who instituted it to appease the ghost of Remus whom he had killed.

Formless or semi-visible shades, sometimes appearing as pale flickering lights or barely-glimpsed human shapes. They were known by their chill and the feeling of unease they produced rather than any consistent visual form.

Caused illness, bad dreams, and madness in household members. Could possess the living or drive them to self-destructive behavior. Were believed to consume the offerings left out for them, and grew more aggressive if not appeased.