Pikipedia:Spoiler

In fear of ruining the ending/key part of the game for the player (before he/she has experienced it him/herself), an article or section may be marked for spoilers in the hope that the section can be avoided.

In order to do this, use the following code:

{{spoiler}}
BODY
{{endspoiler}}

or, to hide it, this:

{{spoiler section
|title=TITLE
|body=BODY}}