NeoXal is a rare Runeword created by combining a Neo Rune of Ritual and a Xal Rune of Invocation.
How to Create NeoXal
You can create NeoXal by adding the rare Neo Rune of Ritual and the rare Xal Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Neo - Deal damage after not taking any within 2 seconds.
(Resets if Invulnerable.) (200)
Xal - Gain 20% Maximum Life for 6 seconds. (200)
Overflow
NeoXal can not overflow because the amount of Offering you receive from the Neo Rune exactly fills the required Offering of the Xal Rune.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.