LithTal is a legendary Runeword created by combining a Lith Rune of Ritual and a Tal Rune of Invocation.
How to Create LithTal
You can create LithTal by adding the legendary Lith Rune of Ritual and the magic Tal Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Lith - Stand still while fighting for 0.31 seconds. (25)
Tal - Invoke the Spiritborn's Pestilent Swarm, dealing damage to enemies. (100)
Overflow
LithTal can not overflow because the amount of Offering you receive from the Lith 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.