I think you managed to get around the 'how to make fire funny' conundrum really well! It totally makes sense that laughter itself would disperse the boggart, and that Tobias would break into hysterical laughter once he realized the fire was not real and not harming him. I thought he was a neat, neat character. I sensed a bit of a hint going on here, yes? I think you nailed Neville's fear of fire after the incident with the hat for sure. And the idea of a boggart infestation was totally unique and well-plotted. Nice job, why were you so down on it??
~Gina :)

I am very impressed with this piece! What a smart way to incorporate boggarts!!! I actually felt like I was there, and Tobias felt like he belonged. How do you do it? Gah! I love how Neville's Boggart made sense, and the juxtaposition of him being in Snape's dungeons made it even better!
If I had to find anything to change, it might be Professor McGonagall's character. She needs to be a bit more brisk and stern in manner. Perhaps add in things like her bun being tight, or looking none to pleased at the prospect of banishing boggarts. You have great attention to detail, so I know you can strengthen McGonagall a little more. I realize the story isn't about her, but rounding her out a little more in the beginning will help make the situation seem even more real!
Overall, though, I really enjoyed this story! Good luck on the challenge. :D

~Nagini Riddle, a fellow Boggart challenger