It can be crafted without a Science Machine using 3 Cut Grass and 1 Spider Gland. Upon crafting the Telltale Heart, the player who crafted it will lose 40 Health. If a player does not have enough health, they will not be able to craft it. If they lose the health while crafting, crafting will reduce them to 1 health, after which they will most likely die to the other damage source, such as freezing or fire.
After a living player gives the heart to a ghost, the living player receives 80 Sanity, and the ghost is revived with an additional 25% (1/4) of their maximum health removed along with normal resurrection penalties. The health penalty received by a Ghost using this item can be removed through the use of a Booster Shot. Ghost Players cannot haunt the heart to revive, they must have it given to them by a living character.
Players who have recently revived someone will be identified by a different examination quote.
- It is advised to stockpile a few Telltale Hearts when the character has full or nearly full health.
- If a player died and no Spider Gland is currently available, the recently deceased are able to haunt a Spider and let the alive players kill it to get a guaranteed Spider Gland.
- The name of this item is a reference to Edgar Allan Poe's short story, The Tell-Tale Heart.
- Telltale Hearts stored in a Chest will produce an audible heartbeat, and multiple ones will sound like rain striking a tent. This enhances the reference to Poe's story, in which the main character has auditory hallucinations that leads him to believe that the heart of the victim he murdered still beats under the floor where he hid the corpse.
- Walters quote suports this.
- Armor used to reduce the health cost of this item, but this was patched out.
- It used to cost 5 Cut Grass to make a Telltale Heart.
- Abigail cannot be revived and attempting to generates a unique character response. According to Wickerbottom's, this is because her soul is already bound to her flower.
- The name of the Telltale Heart is a portmonteau of the famous line to live to tell the tale, as stated by Wortox.
- "Her spirit is already bound to something in this world." - Wickerbottom attempting to revive Abigail.