wp-spoiler-alert

This plugin adds the shortcode [spoiler] to WordPress. Any content
wrapped inside this shortcode is blurred out. It can be revealed by
clicking on the blurred content.

The shortcode takes a mode parameter, which defaults to block. This
wraps your content inside a div. To add spoilers that are inside to your
text use the mode inline.

Eg:- Some [spoiler mode=’inline’]super secret stuff[/spoiler] here!

Credits

• Inspired by the spoilerAlert jQuery plugin by Joshua Hull