Marvel Comics’ Spidey-sense must be tingling. The estate of Jack Kirby, who co-created most of the comics behemoth’s most popular superheroes, is suing the company to terminate the copyrights on those characters, according to The Hollywood Reporter’s THR, Esq. blog. The suit claims non-exclusive control, but that still means that, should it win, the estate would be able to license to other studios characters with movie franchises already in the works. X-Men, Iron Man, Captain America and the Fantastic Four could all potentially lose their copyright statuses.