A Lightning Mirage is a blue-coloured non-targetable mirage created by monsters with the "Lightning Mirage when Hit" (Lightning-Retaliation) monster modifier when hit.
Its name originates from a former nemesis modifier of the same name: Lightning Mirage. It was also previously a part of the archnemesis modifierStorm Strider (of Storm-stridingof Storm-striding Intrinsic 50% of Physical Damage Converted to Lightning Damage (Hidden) 30% increased Lightning Damage (Hidden) Gain 25% of Physical Damage as Extra Lightning Damage (Hidden) +40% to Lightning Resistance (Hidden)).
Similar to the "Caustic Orb on Death" or "Exploding Orbs" monster modifiers, the mirage will chase the player character for a duration and explode on contact, dealing Lightning damage and inflicting Shock. Since there a delay between contact and the actual explosion, players can move away from the mirage to avoid damage.
Lightning Mirages spawned by monsters with the Storm Strider modifier now spawn a short distance away from the player, instead of right on top of them. Monsters with this modifier now have a 2 second global cooldown for Triggering a Lightning Mirage when Hit (previously 0.75 second), and Lightning Mirages now have a 1 second cooldown until they can use their explosive skill (previously 2 seconds).
Archnemesis modifiers have been rebalanced and added to the core game. Existing Magic and Rare monster modifiers have been replaced with Archnemesis modifiers.
Bloodlines and Nemesis have been removed from the core game. Some of their modifiers have been incorporated into the new monster modifier system.
Now also spawns from archnemesis modifier Storm Strider. [Undocumented This change was not documented by any official sources. It was discovered through player testing or datamining.]