Calynthia Powder is a bright purple colour. As a powder, it can be mixed into liquids and ingested, such as water or blood.
The drug is presumably magical in nature, and is used to affect the dreams of the person being fed it – usually without their knowledge. The drug makes the user more suggestible, especially when in a dream state, allowing anyone present while the user is dreaming to plant suggestions in their mind – while full control is not possible, it can be used to manipulate the person.
A person under the influence of Calynthia Powder will sleep more deeply, which makes the manipulation easier, as they will not wake when they otherwise would. Repeated doses will upset the sleep cycle of the user, making them sleep longer, dream less and awake less refreshed.