A potion of sleep, also known as potion of somnolence, was a powerful potion that put the imbiber to deep sleep and was extremely dangerous in its undiluted form. The hazy liquid of the potion was swirled with hypnotic patterns. The concentrated liquid that composed a potion of somnolence created a puff of white mist when the vial was uncorked.
Undiluted, potion of somnolence was an incredibly powerful and addictive substance. Just one sip of the highly watered down soporific liquid (one drop of the potion in a vial-full of drinking water) was enough to send the user to sleep in less time than it took to count down from ten. A typical dosage was just one mouthful and it was enough to last several hours.