A spoiler is a summary or description of a narrative (or part of a narrative) that relates plot elements not revealed early in the narrative itself. Moreover, because enjoyment of a narrative sometimes depends upon the dramatic tension and suspense which undergird it, this early revelation of plot elements can "spoil" the enjoyment that some consumers of the narrative would otherwise have experienced.

The term spoiler is often associated with specialist Internet sites and in newsgroup postings. Usually, the spoiling information is preceded by a warning ('SPOILER!'), or the spoiler itself has to be highlighted before it can be visibly read on the web page by those keen for details and not fazed at the thought of such potentially plot-revealing information. Occasionally, these warnings are omitted, accidentally or deliberately (see below), and some unwitting readers have had films, books, television programmes and other works that they were looking forward to experiencing spoiled.

Spoilers are things in a work of fiction that spoil the excitement. For example, the fact that Darth Vader is Luke Skywalker's father in Star Wars is a spoiler. It reveals an unexpected plot twist.

Ben 10verse Pedia contains spoilers about all of the seasons and episodes made thus far. And because most fans of Ben 10 have seen all of the episodes this isn't a true problem, but beware those of you who haven't seen them all.