Mox Beacon

The Mox Beacon was a device created by Ravidel from the Mox Ruby, Mox Jet, and Mox Sapphire taken from Liana of Minorad during a battle at the Dueling Chasm of Golthonor. It set off a powerful magical signal to all of the planeswalkers who had betrayed either Jared Carthalion or Ravidel. Daria was the first to arrive on Corondor, though many others, including Sandruu, Taysir, and Teferi were attracted to the signal.

A similar device was created by Niv-Mizzet prior to the War of the Spark.