Ever since Nick Fury appeared in the after-credits scene of Iron Man, various movies have attempted to jump-start their own cinematic universes with this method. The after-credits scene has become an expected mainstay of comic book movies, with many theatergoers now trained to stay in their seats through the entire credits just in case there's something extra at the end. Those who stuck around for the credits of the Sonic the Hedgehog movie will be rewarded for their patience, as the movie does indeed ave an after-credits scene. Please note that this post will have MAJOR SPOILERS for Sonic the Hedgehog.
Following the climactic battle between Sonic and Dr. Robotnik, the Sonic the Hedgehog movie sees Sonic officially move in with his human friends. After the title card is shown, we get an update on Dr. Robotnik's situation, as he is now stranded on a mysterious mushroom planet with a much more video game-accurate appearance. Dr. Robotnik on this planet was actually shown in one of the trailers, so it's a bit odd that the trailers gave away one of the last scenes in the movie, but in any case, this shows that a Sonic the Hedgehog movie sequel will likely feature a crazier version of Robotnik that has even more in common with his video game counterpart.
The actual after-credits scene in the Sonic the Hedgehog movie comes after the Wiz Khalifa "Speed Me Up" song. In it, we see Sonic's friend Tails appear on Earth, using some kind of tracker to find Sonic. "If these readings are accurate, he's here. I found him! I just hope I'm not too late." Tails then uses his tails to hover over the Montana wilderness in search of Sonic, setting up the plot of the potential sequel.
A Sonic the Hedgehog movie sequel has yet to be officially announced, but it seems likely. Not only does this Sonic movie after-credits scene clearly set up a story for the sequel, but the first movie is on track to make quite a bit of money at the box office. Plus, the Sonic movie director Jeff Fowler has already teased a "bright future" for Sonic.
It's unclear if Sonic and Tails actually know each other in the Sonic the Hedgehog movie universe, as Sonic was sent away from his home at a young age, but answers should come in the movie sequel.
Sonic the Hedgehog is in theaters now.