Tomb of Horrors
Found in the Garden of Graves. An intricate magical contraption of iron rods and wooden shafts, crossing and crisscrossing each other. At each intersection, a rune is stamped on wood and metal, and several of the larger joints are adorned with gemstones. At its top, the device comes to a pyramidal peak, with prongs holding a gleaming emerald. The device channeled eldritch energy from the Feywild to an unknown location.
The Heroes destroyed it, thus curing the undead troubles in the Garden of Graves.