Resonance stone

Resonance stones were psionic items that allowed a mind flayer to psionically imprint an emotion upon them.

Description
An individual resonance stone was an egg-sized, cut and polished crystal or gem.

Powers
When activated, each resonance stone attempted to force the desired emotion onto anyone within twenty feet.

These stones were often used in illithid domiciles as decorations that simulated a chosen pleasant emotion. In this use, the stones were able to elicit satisfaction, anticipation, elation, or satiation in nearby people. When they were used like this, illithids often treated them like humans did with familiar smells in their homes.

However, these stones had another use of a defensive nature. They would sometimes be set in strategic locations around illithid colonies and elicit emotions such as fear, disgust, exhaustion, or apathy in victims.

Resonance stones used to induce fear were scattered across the 20 miles surrounding the illithid city of Oryndoll.