Before MrBeast became a professional YouTuber, he commented "i want a shotout bro plz" and "please" on a video called "this is a reply to badger5402's comment" back in 2012 on thejenniningsproject's channel. He asked thejenniningsproject for a shout out too. He later got a shoutout in the video "shutout to MrBeast6000".
In the summer of 2020, a Reddit user discovered this comment and then posted it on Reddit. The video grew a lot of popularity since then because this comment from MrBeast was discovered on such a small channel.
The comments on all the thejenniningsproject's videos have now been turned off.
Other similar events
Buddster, a gaming YouTuber, has uploaded a video titled Mr. Beast... do you remember me?🥺. Before Jimmy became famous, Buddster asked Jimmy: "can you just remember me when you get famous?", then Jimmy replied with "yes bae". MrBeast comment on this video to make sure that he still remembers this person.