The Invisible Spray comes in a blue bottle that has the product's name written in red text within a yellow background on the can. There is also a warning label with a red background at the bottom.
Role in episode
SpongeBob and Patrick use the Invisible Spray to prank the people of Bikini Bottom by making themselves invisible and pretending to be ghosts.
Towards the end of the episode, Mr. Krabs throws water at SpongeBob and Patrick to make them visible again in a bathroom stall at the Krusty Krab, where they were revealed to be naked, due to the spray staining clothes. Once SpongeBob and Patrick walk out of the bathroom after apologizing to Mr. Krabs for threatening to burn a dollar, the latter shines a spotlight on them and the audience humiliates them for being nude in public.
This results in the two regretting buying the spray in the first place and agreeing that they should have bought the whoopie cushion instead.
When Frank holds the Invisible Spray bottle, the bottom of the bottle has a danger label on it. However, in every other shot of the spray, the label is missing.
The spray should not work at all since it comes off with water, and SpongeBob and Patrick live underwater.