CirMot is a rare Runeword created by combining a Cir Rune of Ritual and a Mot Rune of Invocation.
How to Create CirMot
You can create CirMot by adding the magic Cir Rune of Ritual and the rare Mot Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Cir - Cast the same non-Channeled Skill 3 times in a row. (50)
Mot - Gain 1 |4 shadow:shadows;, from the Rogue's , reducing damage taken per shadow. (150)
Dark Shroud
Overflow
CirMot can not overflow because the amount of Offering you receive from the Cir Rune exactly fills the required Offering of the Mot Rune.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.