The Skrulls are mean, they're green -- and, apparently, they're co-owned by Marvel Studios and 20th Century Fox. According to "Guardians of the Galaxy" director James Gunn, screen rights for Marvel's premiere shapeshifting alien race are shared by Marvel and Fox -- with some exceptions.
When a fan asked why "Guardians of the Galaxy" could use the Kree but not the Skrull, Gunn responded,
Some specific Skrulls are at Fox. But the Skrulls as a whole are co-owned. https://t.co/2hJYkskLZ3
- James Gunn (@JamesGunn) July 6, 2016
Considering that the Skrulls were introduced in 1962's "Fantastic Four" #2, it's no surprise that at least some of the rights belong to Fox, which also currently holds screen rights to the "Fantastic Four" franchise. They also featured prominently in Brian Michael Bendis and Leinil Francis Yu's "Secret Invasion"; in this crossover event, the Avengers learned the shapeshifting Skrulls had infiltrated their own ranks as well as a good chunk of the world population.
While Gunn didn't specify which Skrulls are exclusively at Fox, it's likely Super-Skrull -- a Skrull artificially engineered to have the Fantastic Four's power sets -- is one of these, as his abilities are so firmly linked to Marvel's First Family.
Gunn recently wrapped filming for "Guardians of the Galaxy Vol. 2," which stars Chris Pratt, Zoe Saldana and Dave Bautista and opens on May 5, 2017. Whether or not the Skrulls appear in this film, however, is yet to be seen.