So, this was a YouTube video which was poorly done (the scenes were just still drawings made using MSPaint). The video was a 5-minute short that focused on Mario going to work, where chaos ensued, and at the end of the short, he is fired.
There was a remake of the video which was made with Flash that had animated scenes and was better than the original video.
The original video was available on YouTube, while the remake is still available on Newgrounds.
What intrigues me the most is that the original version is completely lost and only 2 stills have been resurfaced: one showing an MSPaint drawing of Mario walking to the office, and the other showing a poorly done title card.
The Newgrounds remake was animated using Flash and it isn't lost media since you can use Ruffle to watch the video.
I remember that MSPaint video! It was so bad it was good 😂. It's a shame it's lost though. Those simple sketches had so much charm.