YaxThul is a rare Runeword created by combining a Yax Rune of Ritual and a Thul Rune of Invocation.
How to Create YaxThul
You can create YaxThul by adding the magic Yax Rune of Ritual and the rare Thul Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Yax - Drink a Healing Potion. (200)
Thul - Invoke the Sorcerer's , inflicting Freeze and Vulnerable onto enemies. (400)
Mystical Frost Nova
Overflow
YaxThul can not overflow because the amount of Offering you receive from the Yax Rune exactly fills the required Offering of the Thul Rune.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.