There are plenty of examples of how not to pull a prank on a rival fanbase. You probably shouldn't kidnap a live mascot. You also shouldn't teabag a passed out drunkard. Those sorts of pranks usually lead to jail time. A couple of daring Borussia Dormund fans, however, have found the perfect mix of slightly illegal breaking-and-entering and relatively harmless mischief.
Dortmund is the current champion of Germany's domestic soccer league, the Bundesliga, which is typically dominated by Bayern Munich. To reaffirm their superiority, Dortmund fans decided to hit Bayern fans where they live. The Allianz Arena in Munich, home to Bayern and 1860 Munich, another local club, is one of the most technologically advanced stadiums in the world, with a luminous exterior that can change color depending on which team is playing (red for Bayern, blue for 1860 Munich, or white for the German national team).
Somehow, Dortmund fans managed to break into the Allianz, tag a few windows with the BVB logo, and change the stadium's color to Borussia Dortmund's iconic yellow.