Yux

Yux are X-shaped creatures that were created by X-Naut PhD and can create Mini-Yux to create barriers around them. They appear in Paper Mario: The Thousand-Year Door. They are first encountered in the Great Tree where they are used as security by the X-Nauts. Later they appear on the X-Naut Fortress on the Moon, but are less in number here.

The Yux are notable in that their beam attacks pierce all Defend Plus and Damage Dodge badges that Mario and his partner have equipped. This means that full damage is taken if no guard is performed, and only one damage is blocked with a regular Guard. The Superguard prevents damage, however.

Trivia

 * Similar creatures called Barribads, appear in the game Super Paper Mario; they resemble Yux in how they form protective barriers, and their faces are physically similar.
 * Another Paper Mario: The Thousand-Year Door creature known as Grodus X also resemble Yux. While they are small and protect Sir Grodus in a method that is similar to Mini-Yux, they are the same green color as Yux, and are also cross-shaped (though with smaller arms). Additionally, a Grodus X's single eye looks like a Yux eye.
 * There is a Sammer Guy in Super Paper Mario called Yowling Yux.