Continuity mistake: After the campers take over the camp, many counselors are tied to trees. When the kids are putting honey on Lars, the left strap of his tank top falls down. In the next shot of Lars crying with the deer, the strap is back upon his shoulder. (01:09:19)
Continuity mistake: The scene of the kids playing on the blob when they first arrive at camp is the same scene towards the end after Pat takes over.
Continuity mistake: After Lars makes the children do a Buddy Check in the lake, the nurse says something like "Well I see that you have a lot of power" and then walks past him. But when the shot zooms out, she is no longer on the screen.
Continuity mistake: The stack of books falls over when Roy breaks into the room. However, when they leave, the same books are stacked perfectly.
Continuity mistake: The nurse's hair changes color throughout the movie.
Answer: Could be he was smart and was advanced several grades. Could be a combined middle school/high school that's just called a high school.
LorgSkyegon