It could be Malfoy. He often has a vendetta against Harry and might have found a way to make him collapse during potions class, either by tampering with his ingredients or distracting him in a way that leads to a mistake in the potion - making process.
A new, mysterious character could be responsible. Maybe there's a new student or a hidden enemy in the school who has some ulterior motive against Harry and decides to target him during potions. This character could have used a very subtle form of magic that's hard to detect, like a charm that slowly affects Harry's strength as he works on the potion.
It's also possible that it was Snape, in a more complex scenario. Although he is the potions master, he might have unknowingly set up a situation where Harry collapses. For instance, if he assigned a particularly difficult potion that was too much for Harry's current abilities, and due to Snape's strict and unhelpful teaching style, Harry couldn't ask for proper guidance and eventually collapsed from the stress and difficulty of the task.
Look to Chapter 140 for the clearest answer. It begins with In the evening, the setting sun was like blood, dyeing the entire earth a..., keeps building through Although there had been a cool breeze in the mountains in the afternoon,..., and lands on I was just joking, just joking." Seeing that.
Chapter 172 is the strongest chapter-level answer because it starts from Not only Shu Yan, but the entire internet was shocked when they saw Su... and follows through on Where's the chaotic scene I was anticipating?. The payoff is that the chapter closes with "Jiaojiao, are you surprised?
A practical answer is Chapter 202, because it turns the idea into a concrete scene. The chapter opens with Jiang Li couldn't believe it, "Just to take a picture?" "Yes, just to take..., adds pressure through That scream immediately woke up the newly asleep An An too., and ends on Give me the.
If you want the clearest chapter reference, go to Chapter 140. Early on, In the evening, the setting sun was like blood, dyeing the entire earth a...; later, the chapter leans on Although there had been a cool breeze in the mountains in the afternoon,....
Look to Chapter 166 for the clearest answer. It begins with Only after everyone in the small courtyard had left, did Zhao Lang stride..., keeps building through Through the window, he saw the girl sitting at the table reading, her face..., and lands on However, after interviewing the villagers, no.
Chapter 189 is the strongest chapter-level answer because it starts from Seeing his painstakingly planted roses trashed like this, even as a fan of... and follows through on Just after coming out of the bathroom, he saw the landlord's family all....
The best chapter pointer here is Chapter 157, ""Forced onto Liangshan". It opens with It was already the last day of Flash Change in his dream. and closes on I'm laughing myself crazy, do actors all have such strong conviction?]....
The best chapter pointer here is Chapter 169, "This is What Happens to Show-offs!". It opens with Everyone: "What?!" Seeing the shocked and bewildered expressions on their... and closes on Wen Jiaojiao, as if to prove herself to Jiang Li, rolled up her sleeves....
Look to Chapter 165 for the clearest answer. It begins with How come everyone else got a solid six points, and he ended up with just..., keeps building through Director Sun spread his hands, "Our staff calculated the total score with..., and lands on Various explosive Weibos sprang up like.
If you want the clearest chapter reference, go to Chapter 210. Early on, This was Zhao Lang's first public appearance.; later, the chapter leans on He was dressed in a set of black and white local attire, with a simple....