Invisible Spray is a spray that makes anything it touches invisible. In the episode "Pranks a Lot," SpongeBob and Patrick bought it from Frank at the Palace of Pranks. It can stain clothes. Mr. Krabs threw water at SpongeBob and Patrick to make them visible again after they made themselves invisible.
The Invisible Spray is a blue bottle that is pretty small in height. It also has "Invisible Spray" written in red with a yellow background similar to the Exploding Chewing Gum. There is also a "warning" box with a red background at the bottom.
SpongeBob and Patrick used the Invisible Spray to prank the people of Bikini Bottom, by making themselves invisible and pretending to be ghosts. At the end of the episode, Mr. Krabs threw water at SpongeBob and Patrick to make them visible again at the Krusty Krab, and they were revealed to be naked, so everyone there made fun of them.
When Frank was holding the Invisible Spray, a the bottom it said "danger." However, in every other shot of the Invisible Spray, the "danger" part is missing. This may be because the "danger" part is a separate sticker and was ripped by SpongeBob and Patrick.