Invisible

Invisible is a status effect in the Paper Mario series. When affected, the character cannot be attacked; all attacks will go right through.

Paper Mario
Repel Gels are the main way to become invisible in this game. The status is indicated by a square divided horizontally into black and white segments. A circle is also divided in half into black and white, with the white half on the black background and the black half on the white background. The entire symbol switches shades repeatedly.

The player can also use Lady Bow's Outta Sight ability to become invisible and avoid enemy attacks; however, this can only be used for one turn at a time.

The only enemy to give the invisible status to its allies are Grey Magikoopas.

Paper Mario: The Thousand-Year Door
In this game, Boo's Sheet replaces the Repel Gel. The indicator in this game is a semitransparent smiling face. In addition, some Recipes such as the Kooky Cookie and Love Pudding have a chance to cause the eater to become invisible. Also, a Boo from the audience may appear and pass through anyone in battle, turning them invisible for one turn.

Similar to Lady Bow from the previous game, Vivian can also help Mario avoid damage from attacks by enemies, by using her Veil move to pull him into the shadows where they can hide.

Princess Peach, with the help of TEC, becomes invisible, by creating an Invisibility Potion from other potions (the Orange, Red and Blue potions). She reverts to normal state with the help of the Green Potion. However, rather than Mario's semitransparent appearance, Peach's body is completely invisible to the player. She also needs to take off her clothes which the Invisibility Potion has no effect on, and that's why.