Sartor, Magnetic Monster, is a Unique Primordial Scavenger found in the Battlefields of Eternity in Act V of Diablo III.
In combat, it has Jailer, Nightmarish and Mortar affixes. In addition, as its title implies, Sartor calls precision meteor strikes (both normal and molten), similar to those that naturally occur across the zone, with little cooldown.
Visually, Sartor's armor crackles with lightning.