Harry Potter theory fans were convinced would happen in the books

A Harry Potter theory that fans thought would have come to fruition, but never did, is circling the Potterheads world.

There's a Reddit thread for Harry Potter fans, that asks: "What were some perfectly plausible theories that turned out to be false?"

Many Potterheads have responded with theories they were convinced would come true. One that has got fans talking is the idea that Neville Longbottom's toad would turn into something - AKA - that he might be an animagus.

A fan said: "I really expected Neville's Trevor to develop into something. The little sucker was frequently found in odd places. But then, psych! It was Scabbers."

Neville was often losing Trevor throughout the series, almost like Ron was often losing Scabbers. In the third film - Harry Potter and the Prisoner of Azkaban - we find out that Ron's pet rat Scabbers is actually Peter Pettigrew, who had been hiding from Lord Voldemort.

He had managed to hide for 12 years before Sirius Black and Professor Lupin reveal his true identity. Some fans also believed Trevor would have a similar story and others just really liked the idea.

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One said: "I wonder if Trevor was ever in the running to be Pettigrew, but the introduction of Crookshanks made Rowling settle on Scabbers."

Another added: "This. So much this. Why wasn't Wormtail, just Wartskin or something? I mean Trevor never became relevant, at all, just wasted potential."

Though someone else, who didn't believe this would ever happen, said: "I doubt everyone thought anything, I didn't think twice about Trevor since he never was relevant.

"The only time I ever thought of Trevor, was AFTER we learned about Wormtail etc."