YaxRandom Rune is a magic Runeword created by combining a Yax Rune of Ritual and a Random Rune Rune of Invocation.
How to Create YaxRandom Rune
You can create YaxRandom Rune by adding the magic Yax Rune of Ritual and the magic Random Rune Rune of Invocation to a two-socketed 
Helm, 
Chest Armor, 
Pants, or 
Two-Handed Weapon.
Overflow
YaxRandom Rune can not overflow because the Random Rune Rune does not have an overflow effect.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.
Legions
Helltide