From Liquipedia Dota 2 Wiki
Mjollnir is a situational late game item. Usually purchased for farming and increased attack power on ranged heroes or when an Assault Cuirass already is built on the team. Mjollnir can be disassembled.
Places a charged shield on a target unit. When affected unit is attacked, there is a chance that lightning will strike the source of damage and other nearby enemies.
- Cannot trigger more than once per second.
- The lightning bounces only to units within a 900 radius of the charged unit. It cannot bounce to invisible units or units in the fog of war.
- Has no effect if cast on a unit that already has a Static Charge active on it.
Grants a chance to release Chain Lightning on attack, dealing damage to multiple targets.