The Demon Behind Glass

This is based on my experiences with the National Health Service. Statted for LOTFP .

The Demon Behind Glass		XP - 100
AC - 10	Hit Dice – (As PC)	Move – Static/Human
Attacks - 1	Damage - 1d6	Morale - 8
A floating pane of glass, visible only from the front. Behind the glass sits a blotched and haggard demon with pin-prick eyes. He looks at you, silently mouths your name, and draws one stroke in his book. You lose one point of CON. It does this, slowly and deliberately, once per turn. Break the glass, (1hp) and you swap places with the demon. It immediately tries to throttle the nearest person whilst screaming with laughter. If it dies, you are released.
You have the demons book. The more you use it, the more like the demon you become.