It was the quarter-finals of DreamHack's winter tournament in Sweden, and LDLC were dominating Fnatic with a nine round lead in a game of Counter-Strike: Global Offensive. Fnatic then went on a blistering run, and won an unlikely victory.
How were they able to turn things around so convincingly? By using a boost move (whereby one player jumps on the head of another) to reach a relatively unknown vantage point on the Overpass map. Then, utilising their overview of the map, they were able to defeat their opponents 16-13. Quite the turnaround.
It's not crystal clear whether it's an illegal tactic, but that didn't stop LDLC from lodging a complaint. Referees called foul play, flagged the use of "texture transparency and (an) immortal bug," and then ordered that the match be replayed.
This decision was itself rendered moot when Fnatic forfeited the match and allowed LDLC to progress in their place to the semi-final against Na'Vi, a game which they duly went on to win. LDLC then played Ninjas in Pyjamas in the final, and won that too, thus winning the DreamHack CS:GO Winter 2014 Championship and a $250k prize. Congratulations to them.