Bill Gun
The title of this article is conjectural; an official name for the article's subject has not been found, so it has been given a fitting title by the editors. If an official name is found, then the article should be moved to its appropriate title.
The Bill Gun is Roy Koopa's signature weapon in New Super Mario Bros. U, New Super Luigi U, and New Super Mario Bros. U Deluxe. It is a variant of the Bill Blaster, but it can be moved up lanes depending on which one Roy is on. When Roy uses this weapon, the force of the Bullet Bill pushes him backwards a little and prevents him from moving, leaving him vulnerable to jumps. It replaces Roy's wand from the other Super Mario games.
When Roy is hit, he lets go of the gun but it still stays in his hand. The gun "travels" with him in the same direction as him in his defeat animation despite having his hands open and him not holding it.