Jack the Time Traveller is a popular internet meme featuring a character who journeys through different eras to deliver unexpected news or witness historical milestones. The humor typically stems from the juxtaposition of modern knowledge against historical contexts, often resulting in shock or confusion from the 'locals' of that time period. This template gained traction on platforms like Reddit and Twitter as a way to comment on current events by pretending they were predicted or prevented by a time traveller. It’s frequently used to mock past mistakes, celebrate technological leaps, or create absurd 'what if' scenarios involving Jack’s interventions in history.