The original Endgame fan theory and its connection to Spider-Man: Far From Home originated from Reddit.
Spider-Man: Far From Home offered up all kinds of crazy MCU elements for the future, leaving fans demanding answers and a slight sense of paranoia about the third installment.
There are SPOILERS for Spider-Man: Far From Home below, so read ahead at your own risk.
It looks like Spider-Man: Far from Home may have confirmed a popular fan theory from Avengers: Endgame.