This appears as a large sundial, mounted on a carved marble block, sitting in the court yard of a ruined castle. It stands over six feet tall, with it's central blade at least a foot of that height. It will radiate strong magic, if tested. Though all the time markings for the day are in a long-forgotten tongue, the design of the item makes it clear what its apparent purpose is.
Apparent is the active word here, because this device was actually used as a strange method of sacrifice in elder days. It's purpose now is completely forgotten. Anyone touching the sundial during daylight (touching it at night is safe) is cursed with accelerated aging. Each day, the victim(s) must roll a Saving Throw vs. Magic, or age one year! Long lived races have more time, of course, but even they will succumb to the curse eventually.
It may be several days, or even weeks, before the curse begins to show on the faces of the victims, by which time, they might be far away from the sundial. A successful Remove Curse only halts the artificial aging for that day only.
The victims can only become clear of the curse by destroying the sundial (preferably without physically touching it). Upon doing so to the the GM's satisfaction, the curse will lift, though any aging that occurred because of it remains.