C.S. Lewis' Dining Chair

Origin
While the original owner is believed to have been a respected (yet horribly lazy) dignitary of the 18th century, Mr. Lewis is credited as its most influential owner.

Effects
The chair, which inspired both the incidences in 'The Voyage of the Dawn Treader' and 'The Silver Chair' (though the latter was amped up to distinguish between the two times it was used), creates a lethargic toxin which infects anyone who sits in it, until they fall asleep indefinitely. Removing the person from the chair will only reverse the effects if the person has yet to fall asleep - if that fails to occur, the sleeping person will only awaken by oral ingestion of an anti-toxin.