The Fantastic Four is a superhero team from Marvel Comics that is based in New York City. Their base of operation is the Baxter Building. The team is made up of Mr. Fantastic (a.k.a. Doctor Reed Richards), Susan Storm (a.k.a. Invisible Woman), Johnny Storm (a.k.a. the Human Torch), and Ben Grimm (a.k.a. The Thing). Together they battle the evil ruler Doctor Doom. Other enemies are Mole Man and the Skrulls. The Fantastic Four has only appeared so far in Earth's Mightiest Heroes, and the Thing is the only member to appear in Ultimate Spider-Man, Avengers Assemble, and Hulk and the Agents of S.M.A.S.H.. The others made cameos in Hulk and the Agents of S.M.A.S.H..
There are various origin stories for the Fantastic Four, but this is the basic one. The Fantastic Four was a team of scientists and astronauts who were doing experiments in Space. An accident on return to earth happened. The ship traveled through a Radioactive storm and the team was changed on landing.
In "Ultron-5", Red Ghost with his Super-Apes manages to infiltrates to the home of the Fantastic Four. But arriving he found Black Panther and Hulk, who easily defeat him and his Super-Apes.
In "The Private War of Doctor Doom", The Thing and the Human Torch went to the Avengers Mansion to play cards. Meanwhile, Janet and Tony went to visit Sue and Reed. Doom uses these meetings to attack them simultaneously. Reed did not understand why Doom attack them knowing that they were accompanied by the Avengers. After a fierce battle, Doom decided to release Janet and Sue. It is revealed at the end that the Invisible Woman was replaced by a Skrull.
When the Skrull invasion began, the Invisible Woman (Skrull) sent the Baxter Building to another dimension but the Real Invisible Woman could enter that dimension and return it to its place of origin.
- Despite being owned by Marvel Comics, the Fantastic Four and their related characters (Dr. Doom, Silver Surfer, Galactus, Annihilus, the Skrulls, etc.) can't be used in the Marvel Cinematic Universe because the movie rights, like the X-Men, are owned by Fox, who have made three FF movies so far: Fantastic Four (2005), Fantastic Four: Rise of the Silver Surfer (2007), and the 2015 reboot, Fantastic Four.