WARNING: THIS ARTICLE CONTAINS SPOILERS FOR THE FILM "I Am Legend". BE ADVISED.

Origin

I Am Legend is a Will Smith film from 2007, based on the book of the same name. Before the film was released, it was previewed by test audiences, who disliked several scenes, including the climax, causing the film to be signifigantly altered before its release.
The original ending contained Will Smith's Robert Neville under attack in his own house, where he performs experiments to find a cure for the virus that has vampirised the other humans. The alpha male vampire symbolises that he wants a woman Neville has been experimenting back, so when Neville gives her back, (not carrying the cure) the vampires leave Neville unharmed.
After audiences disliked it, it was changed to have Robert hide Anna and Ethan (two other survivors) from the creatures, he charges at the vampires with a grenade and goes boom.
After the general public heard about this alternate ending, many who didn't have it on the DVD searched it into the good ol' trusty, reliable Internet (namely YouTube). Some decided to create their own spoof versions of the ending, leading viewers to what they think is the official ending, then finding it's a spoof, basically, it's bait and switch. Participants lured in their victims using titles that included text like: "I Am Legend Alternate Ending (that we didn't put on the disc)" (see below for link to example).
Eventually someone uploaded the proper version, spoiling the fun. :'(
Original ending:
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Revised ending:

Derivatives

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