Welcome to the challenge of August, which is going to be all about Time; mostly fiction dealing with Time Travel, but also other topics to do with Time, and the manipulation thereof.

Time travel is not always about the past and present colliding, sometimes things go the other way and the present is visited by the Future; sometimes on a quest to prevent a specific outcome, sometimes as a casual spectator with added knowledge, sometimes it’s not even people, but technology that then gets used (and abused) before its time.
And so todays prompt is about stories where modern characters suddenly have to reckon with things from the future- what are your favorites? Do you enjoy this trope?

Bonus Prompt: What are the worst / most underwhelming examples of this trope?

Extra Bonus Prompt: What story/universe should have been more affected by exposure to people/technology from the future?

Paradox Bonus Prompt: What Sci-fi invention would you introduce to present day society, and would it backfire horribly or not?