Mostly these are forgotten upon fully waking or soon afterwards, in the same manner as dreams.
However, most people remember the phenomenon of hearing music or seeing things in near-sleep states at some point in their lives.
Victims may have been experiencing waking dreams or sleep paralysis.
The reason for this is ultimately unknown but the most common explanation is that this prevents one from acting out one's dreams.
Malfunctions of this process can either result in somnambulism (sleepwalking) or, conversely, sleep paralysis—where one remains partially or wholly paralysed for a short time after waking. In a near-dream state, it is common to experience auditory and visual hallucinations.
The Southern African incubus demon is the Tokolosh.
Chaste women place their beds upon bricks to deter the rather short fellows from attaining their sleeping forms.
They also share the hole in the head detail and water dwelling habits of the Boto. In Assam, a north-eastern province of India it is mostly known as "pori" (Assamese: পৰী, meaning "angel").