Ghost Host/Chimps Ahoy - S4-E10
Continuity mistake: In "Ghost Host", Spongebob rips off a bit of sponge and drops it on the ground. Two shots later, his head is back to normal and the sponge on the floor is gone.
Ghost Host/Chimps Ahoy - S4-E10
Continuity mistake: In "Ghost Host", the Flying Dutchman is falling down the side of a cliff. When he lands on the ground in the next shot, the cliff is gone.
Ghost Host/Chimps Ahoy - S4-E10
Continuity mistake: In "Chimps Ahoy", a robot is lying down on a log. The robot gets up and peels the banana one of the chimps was holding. In the next shot, the log has completely disappeared.
Ghost Host/Chimps Ahoy - S4-E10
Continuity mistake: In "Chimps Ahoy", Spongebob removes a helmet he was wearing and holds it in his hands out of frame. In the next shot, the helmet is missing and not on the ground.
Answer: I believe this is the Season 6 episode "Spongicus".