BacChac is a legendary Runeword created by combining a Bac Rune of Ritual and a Chac Rune of Invocation.
How to Create BacChac
You can create BacChac by adding the legendary Bac Rune of Ritual and the rare Chac Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Bac - Travel 5 meters. (50)
Chac - Invoke the Druid's Lightning Bolt, striking a nearby enemy. (20)
Overflow
When BacChac overflows, you receive the Chac Rune's overflow effect (Increased Bolts Spawned) 1.5 times.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.