Jazza is a character is a YouTuber who, on his YouTube account, made a video where he took over Drawception using Twitch.
After this, Jazza started appearing in normal games, often as derails or instead of using a generic character. Examples:
People often confuse Jazza as: "guy in red shirt" "Donald Trump" "blonde guy" and "jazza"
People steadily became more annoyed as people became purposely derailing games to include Jazza in them but the trend is steadily becoming more tame.
EDIT: *cough* *no it isnt* *cough*