Will Stone (3.5e Equipment)
From D&D Wiki
Will Stone: This small stone is two inches in diameter, a half an inch thick, and black as night. When initially activated, the owner is surrounded in a shadowy black, multi-faceted cloud. This cloud will record up to one hour of everything within its borders. After the recording is done the owner must then place the stone upon their breastbone, where-upon the stone sinks beneath the owners flesh appearing as a raised circle of skin. While the stone is under the skin the owner is immune to 3 death effects per the Death Ward spell per day. The protection is automatic and only affects the first three effects that target the owner. If the owner dies while the stone is under their skin, their body is under the effects of the Gentle Repose spell for a year and a day and the stone leaves the body. When the stone leaves the body it usually appears on the chest, damage to the body may cause the stone to fall off, roll away, etc. If a sentient being within one alignment step of the, now dead, owner picks up the stone it projects the message that the owner recorded (typically a will) and lets the new owner know that they may replay the message by holding the stone before them and saying play or record a new message by saying record.