The mutants are multiplying! 20th Century Fox has scheduled six Marvel movies through 2021.

Fox owns the movie rights to the "X-Men" and "Fantastic Four" characters. The six mystery movies will hit theaters June 7, 2019 November 22, 2019; March 13, 2020; June 26, 2020; October 2, 2020; and March 5, 2021.

These are in addition to the already-announced releases of "The New Mutants" (April 13, 2018), "Deadpool 2" (June 1, 2018), and "X-Men: Dark Phoenix" (November 2, 2018).

So, what could these six movies be? Likely one will be a follow-up to "X-Men: Dark Phoenix," or perhaps "X-Force," which is in development. Another is probably "Deadpool 3," assuming that the sequel is a smash success like the original. With the Wolverine franchise seemingly at an end, Fox may look to spin off another character — maybe for Jennifer Lawrence's Mystique.

Fox could try to make another go at "Fantastic Four," though the recent reboot was a commercial and critical bomb.