UrLac is a rare Runeword created by combining a Ur Rune of Ritual and a Lac Rune of Invocation.
How to Create UrLac
You can create UrLac by adding the magic Ur Rune of Ritual and the rare Lac Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Ur - Your Minion or Companion kills an enemy or dies. (10)
Lac - Evoke the Barbarian's , reducing your damage taken. (800)
Challenging Shout
Overflow
UrLac can not overflow because the amount of Offering you receive from the Ur Rune exactly fills the required Offering of the Lac Rune.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.