Legal battle
When 'The Terminator' released in 1984, Harlan Ellison was not happy.
The writer argued that the movie was a "rip off" of an episode of 'the Outer Limits' he had produced called 'Soldier', which itself was an adaptation of his book 'Soldier From Tomorrow'.
Thankfully for James Cameron, Harlan and Orion Pictures settled the matter out of court, though the director was unhappy with being accused of plagiarism, and later called the writer a "parasite".