Coin of Time (3.5e Equipment)
From D&D Wiki
Coin of Time: This is a platinum coin that has no visual difference from any other but emits small amounts of magic. You may attune to the coin, in doing so the coin will always land on whatever side you call. You must call your choice out loud before the coin lands. If you don't call out "heads" or "tails" then it flips and lands on a random side like a normal coin. If the coin lands on heads than the next person to touch the coin gains a +4 to AC for 10 minutes, over the course of the ten minutes the creature will also age 4 years. The creature does not die of hunger or thirst, but can die from disease, curses, or old age. If the coin lands tails the first person to touch the coin gains +6 to AC for 10 minutes. Once again however the creature ages 10 years in the ten minutes not dying of hunger or thirst, but they can die due to disease, curses, and old age.
This simple platinum coin could be lost for ages in a pile of mundane coins, untill one day a wizard casts detect magic revealing the magic inside. Attuning himself to the coin and flipping it in the air and calling tails. The coin does as he commands and lands tails up in his hand. Drawing his soul out forming a protective barrier around him, as he begins to age swiftly with every minute that passes he becomes older and weaker untill he drops dead of a heart attack with no culprit in sight.
Weak enchantment;CL 7; ability to cast mage armor; Cost 10 years from your life, 1000 gp, and 500 exp; Weight: 1/50 lb.; Market Price: 5000 gp