2. Prometheus' Last TV Spot Spoiled The Giant Squid
The Secret: That the squid-like creature removed from Elizabeth Shaw's (Noomi Rapace) abdomen mutates into an absolutely gigantic squid and attacks both her and an Engineer.
How It Was Spoiled: The
final TV spot, released more than a week before the film started hitting cinemas, showed a brief glimpse of the giant squid (at the 0:52 mark), which seemed counter-productive to all the previous advertising, that had sold the movie on its mystery, keeping concrete details vague. Considering that probably nobody would've predicted Shaw's facehugger-like birth product transforming into something so large, it completely sucked the air out of what could've been an incredibly shocking moment. Plus, it lets you know that the squid doesn't like the Engineers either...