Continuity mistake: At the start of the fight in the club, the stain on Clouseau's jacket (from the accident with the parrot) is visible. Partway through the fight it has faded significantly. By the end of the fight it has gone. (00:45:00)
Continuity mistake: The President of the US is watching football on channel 1. Dreyfus interrupts the broadcast and an aide flips through the channels to discover that Dreyfus is on all of them - the TV ends up on channel 9. Throughout the rest of the scene, the TV switches back and forth between channels 1 and 9 without human intervention. (00:50:00)
Continuity mistake: After Dreyfus' pirate broadcast we are shown a black and white picture 'taken by a journalist during the broadcast'. The photograph is very unlike any image of Dreyfus' face in his telecast.
Continuity mistake: In the beginning, when Clouseau walks to the door of his apartment, there's a big pile of sugar in the elevator. This pile disappears during his silly dance, but returns when he tears his pants later.
Continuity mistake: When Clouseau, Cato and Olga fall into the river at the end of the film there are two shots of the fall (one from above, one from below). The two shots are different - the people are in different places and there are different amounts of debris and bedding. (01:41:20)
Continuity mistake: When Dreyfus makes the first hole in the ceiling to spy on Clouseau, the latter spills sugar on that spot of the floor. Yet when we look through the telescope, the floor right in front of it has no sugar on it.
Continuity mistake: Inspector Closeau's large rectangular parcel - leaning against the table - changes position while he is opening the door to his flat. (00:13:45)
Continuity mistake: When Clouseau hits Cato with a nunchaku, Cato is holding his pole in the middle. In the next shot, his hands have moved to the bottom of the pole.
Continuity mistake: In the hallway, Clouseau has spaghetti and a french loaf sticking up out of his shopping bag. When he enters his flat, the loaf has vanished. (00:14:05)
Continuity mistake: Clouseau's clothes go back and forth from being wet to dry during his numerous and failed attempts to get into Dreyfus' castle and falling into the moat instead.
Continuity mistake: When Dreyfus goes crazy again he's completely soaked, When he's chasing Clouseau he's suddenly dry.
Continuity mistake: At the very end of the film when the bed crashes through the wall, Olga has disappeared from the very first outside shot. She is then back to the left of Cato in the next shot. This was likely done because she was completely nude and the audience would've got a good look at her.
Continuity mistake: During Oktoberfest when Clouseau is being followed by assassins, one has metal spikes in his chest. They change lengths during the scene. They're longer toward the end of the sequence.
Continuity mistake: During the scene when the U.N. building is disappearing, the top of the building changes. Notice in the other shots, there is some sort of structure atop the building. It is see-through. When we see the effect happen, that structure is gone.
Continuity mistake: When Clouseau is on the front page of the newspaper after being arrested in the Soho club the date on the front of the newspaper is Monday July 12th, but two other events in this film are in October, the beer festival and the disappearance of the UN building. The events of the film don't cover that long a timespan.
Continuity mistake: During Clouseau's visit to the asylum, when a completely soaked Dreyfus finally climbs out of the pond, his clothes have only partially wet patches before he sits on the bench and then they're soaked again.
Answer: Just Invisible. Besides the fact that his eyeball and eyelid remain intact and in the same position, he returns in a full, visible form (possibly in a film logic borrowed from Looney Tunes cartoons) in the next Panther film.