Fan CastingAvengers: Doomsday

Dr. Doom enters Earth-19999 or Earth-616, whatever it is referred to as, he feels that his world, where the Fantastic Four: FIrst Steps will take place is at risk of getting destroyed after him hopefully facing off Galactus and Shall-Bal's Silver Surfer after the Fantastic Four fail to, he takes the Fantastic Four into the MCU hopefully seeing them join him into merging all the worlds into Battleworld for the planet to be protected by every single variant of him and other characters, but well during this Sam Wilson finally forms the new team of Avengers, the Fantastic Four join them talking about Dr. Doom to see if they could help them, and after that the big battle happens.