ZanChac is a rare Runeword created by combining a Zan Rune of Ritual and a Chac Rune of Invocation.
How to Create ZanChac
You can create ZanChac by adding the magic Zan Rune of Ritual and the rare Chac Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Zan - Cast an Ultimate Skill. (150)
Chac - Invoke the Druid's Lightning Bolt, striking a nearby enemy. (20)
Overflow
When ZanChac overflows, you receive the Chac Rune's overflow effect (Increased Bolts Spawned) 6.5 times.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.