"A palm sized disk of jet black plastic, covered in strange runes."
Dangerous grenade that will cause a nuclear explosion able to deal huge, but random amount of damage. It can be somewhat safely used to shoot far away with grenade launcher or a lot more safely used as a bomb to clear out floors before you go in them.
Extreme caution is advised when putting this grenade to use. It can be used repeatedly with Temporal Fugue by allowing your duplicates to throw it, but you should make sure you're at a safe distance before doing so. Using Teleportation and Clairvoyance to send your duplicates into battle from the other side of the map often works.