Back when I was in school (about 15 years old) and I played games, I had a particularly favourite game that I would play. It was a lesser known strategy game made by a single hobbyist Dev.

I was already known in the community for making some mods for the game and chatbots.

What most people didn't know was that I had made a map hack and various other cheats that made it significantly easier to win by reverse engineering the game and modifying the x86 assembly in ollydbg.
One thing in particular I had been working on at the time was a game replay editor. I had reverse engineered the saved game (replay) format and was able to replay them, edit them and generate them.

During one particular match, a person in the community particularly annoyed me and I edited the saved game to change what his moves were and the words he spoke. It made him look a bit like an idiot but IMHO was only a slight exaggeration of the truth.
I posted the game replay on the forums and everyone was in hysterics about the crazy things he did and said in the replay.
As no one knew I had this capability they all believed the replay and even the guy in the replay couldn't believe it himself and didn't understand what happened. He just kept telling everyone it didn't happen and the 'truth is in the pudding'.

Although I originally intended to tell everyone what I did, I never did and whenever the guy entered in to a game everyone would laugh about it and say 'the truth was in the pudding'.

He was no longer annoying me and it sort of made me feel like a god at the time.
So that's my wk65.