“There is much speculation online about Charlie Brown getting rocks in his trick or treat bag while all of his friends get candy.
The most popular theories:
1. Charlie Brown just has really bad luck.
2. Everyone kind of hates Charlie Brown, even adults, enough that they would plan for his arrival on Halloween night by placing a rock near the candy so they could give it to him.
3. The “rock” is not literal, it’s a metaphor for lousy candy, sort of the way the adults in Peanuts cartoons squawk instead of forming words, which we assume isn’t actually happening, but the perception of a child. The same thing is happening with the candy, and thus Charlie Brown’s “rocks” are probably circus peanuts or those orange and black taffys.
My Theory:
The Great Pumpkin does not come visit Linus, and Linus is incorrect about the workings of GP. Instead of visiting a child who believes the most and showering them with Halloween blessings, The Great Pumpkin is a bitter, angry god who punishes a child who does not believe in him.
On this particular year, The Great Pumpkin visited his evil upon Charlie Brown, cursing Charlie Brown’s treat bag. The items that went in were, in fact, candy, but once they crossed the bag’s threshold, The Great Pumpkin’s curse transformed them into rocks.
Okay, there’s not a ton of evidence, but is it any stupider than calling it a metaphor for crappy candy?”