Trevor Nix is a character who appears in Diary of a Wimpy Kid: The Meltdown. He used to live on the top of Surrey Street, but he moved to a bigger house on the Lower Surrey Street, where the Upper Surrey Street kids won't let him sled down their hill and think of him a traitor and the Lower Surrey Street kids still consider him a hill-person, resulting in him having to stay inside year-round. During the snowball battle, the Upper Surrey Street Kids saw a kid running towards them from a couple of houses to the right side of their fort. They were ready to pelt him with a round of snowballs but then somebody recognized the kid, and they held their fire. Trevor Nix was seen running and waving them to get their attention. He was out of breath after he ran and could barely get his words out. They pulled him up over the wall and waited for him to calm down. After he got himself together, he told them what was going on. He said that the Lower Surrey Street Kids had been holding him captive, but somehow he managed to escape. He said the guys were planning something really bad, and he wanted to them before it was too late. He said the Lower Surrey Street Kids were creating a huge stockpile of snowballs, and when it got dark, they were gonna launch into a full-scale attack. But that wasn't even the worst part. Those guys were making their snowballs in the Guzmans' yard, and that's the place where all the dogs are. So that meant they were using yellow snow and who knows what else. Everyone was pretty mad about what the Lower Surrey Street Kids were planning, they were glad that Trevor Nix had given a heads-up. They told him that from now on he can sled on their hill anytime. They agreed they couldn't wait just sit there and wait for the attack, so they started working on a plan. Half of them would sneak down the hill and launch a surprise attack on the kids making snowballs in the Guzmans' yard. The other half would stay back to protect the fort. They sketched the plan in the snow with a stick to make sure they were all on the same page. Greg and Rowley wanted to be part of the sneak attack team. Their group loaded up a few sleds with all the snowballs they had left, and they slipped over the back wall and between some houses. It was getting dark by now, so they knew those guys wouldn't be able to see them coming. When they reached the Guzmans' yard, they stopped and scope out the scene. Sure enough, there was a big group of kids making snowballs at the front by a rock wall. When Baby Gibson gave the signal, they launched the attack. However, the other guys didn't flinch when they hit them. And when they got closer, they realized that Trevor betrayed them. The Lower Street Kids had created decoys to split them up, and that means they were double-crossed by Trevor Nix. They went back to the wall, but by then it was too late because the Lower Surrey Street Kids had destroyed their fort and the wall was in ruins. Towards the end of the story, he is seen playing hockey down at the bottom of the hill with the Lower Surrey Street Kids every day after school.
- Diary of a Wimpy Kid: The Meltdown (First and only appearance)