Amazingly Aimless

In Paper Mario: The Origami King, a plot event in Shangri-Spa is Bowser Jr.'s colors disappearing after taking a bath in the Spring of Jungle Mist. When he emerges from the spring, Kamek says a blank text bubble, whereupon he humorously explains that the shock made the color drain from his typeface.

However, while the speech bubble appears blank, it actually has text in it, which is merely set to 0% transparency - "You're bleached!". As such, it cannot actually be seen in-game under any circumstances, and requires extracting the data from the game's files to view. Interestingly, this text has been translated into all languages the game is available in, and cannot be seen in any of them. The table provides the text and a rough translation of all the language versions.

Source: Scrooge200

(sent the previous ask too early, sorry!! -.-)