People have been "invading the pitch" since probably the invention of sports. Well, maybe aside from gladiator fights and pit battles as you wouldn't wanna get caught down there in 'mortal combat'. There seem to be a few different reasons and types of people who do this.

You have the classic in and out ones where a fan hops the barrier runs onto the field for a couple of seconds or maybe a minute and then makes a successful exit and a clean getaway. Then you have the ones who overstay their welcome and end up getting tackled by security or players on the field. Lastly is the streakers. Someone makes their way onto the field and dons their birthday suit for everyone in attendance to see. The reasons people do this can vary from an adrenaline rush, an attempt to be famous, or on live TV, to people who might just have a couple of screws loose.

During the Buffalo Bills vs the Chiefs game, this guy ran onto the field, and Wide Receiver Stefon Diggs decided to take matters into his own hands and knocked him completely off his feet. Security personnel quickly pounce on him and escort him off the field. I guess it just goes to show you that sometimes the players get fed up and just want to get on with the game.