This here paint is absolutely permanent. It will never come off. So if I see even one drop on anything but wall, I'll have your rear ends cut off... and mounted over me fireplace! So, have fun with the job.
Permanent paint is a type of house paint that appears in and is a major plot point of the episode "Wet Painters".
It is "permanent" white house paint that is stored in a gray bucket. It apparently sticks "permanently" on a surface unless one spits on it.
Role in episode
SpongeBob and Patrick are ordered to paint the inside of Mr. Krabs' house, much to their excitement. However, Krabs informs the pair that the paint is absolutely permanent and strictly warns them not to get paint on any of his expensive treasures, or else he will cut off their buttocks and mount them over his fireplace.
The two use rather small brushes to avoid dripping paint on anything but the wall. Upon (riskily) opening the cans of paint, one drop is released and drips back and forth on SpongeBob and Patrick's tarps, much to their anxiety, only for it to go back into its can. Thereafter, SpongeBob dips his brush into his can and mentally prepares himself to paint the wall for a few hours. Once he does so, he notices the paint's proximity to Mr. Krabs' prized possessions, so he blows it in various directions to prevent it from touching anything.
When the paint is about to reach its peak, SpongeBob blows it away with a hairdryer. This, however, aggravates the situation and creates a giant paint bubble. Patrick blows another one to make matters worse and then proceeds to merge them together and inflate them. Although it seems like they are at risk, the bubble actually benefits Mr. Krabs' house by surprisingly managing to fail at getting paint on anything, except for his first dollar.
This horrifies SpongeBob and Patrick and the two resort to going through several bizarre attempts at removing the paint from the dollar bill, but none of them work. However, Patrick then suggests they grab a dollar from his wallet and replace the paint-covered one, only for him to waste it on a chocolate bar from Mr. Krabs' candy machine.
Once Krabs gets home from the grocery store, he is impressed y the new look of his house, thanking the pair for their hard work. However, he then realizes that they got paint on his first dollar and it looks as though he will cut their butts off, but he does not; he winds up licking the paint off and reveals that it is not really permanent because it comes off easily with saliva and that he likes messing with SpongeBob and Patrick, much to their anger.