YulTal is a legendary Runeword created by combining a Yul Rune of Ritual and a Tal Rune of Invocation.
How to Create YulTal
You can create YulTal by adding the legendary Yul Rune of Ritual and the magic Tal Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Yul - Cast a Skill with a Cooldown. (50)
Tal - Invoke the Spiritborn's Pestilent Swarm, dealing damage to enemies. (100)
Overflow
YulTal can not overflow because the amount of Offering you receive from the Yul Rune exactly fills the required Offering of the Tal Rune.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.