This story is not my usual style of writing...it is a gift for another fimfiction user.
Warning: gross humor
Warning: lots of potty humor
Twilight and her friends leave on a secret mission that will take a few weeks, and they leave Spike alone in the library to guard the Elements of Harmony. Knowing that a changeling infiltration attempt is likely, Spike prepares an unusual defense. Queen Chrysalis will remember, and possibly regret, her attempt at stealing the Elements for a long, long, time.

Seriously, though, if you are turned off by potty humor...don't read this.