​There is nothing sweeter in all of League of Legends than watching someone's bad manners getting absolutely punished. In this ​video by reddit user JC18137, Fiora shows up to absolutely demolish the opposing mid laner, Karthus. 

With only a Wall of Pain to try to slow down the Grand Duelist, Karthus doesn't stand much of a chance. 

Nearly dead, Karthus seems to teleport next to himself out of frustration, but things aren't always what they seem.

Shouldn't have let him live, Fiora. In an awesome display of teamwork, the red team synchronizes their teleports to destroy the enemy Fiora. When Riven shows up next to the minion instead of Karthus, you can see the Fiora pause in confusion. That's all the time Riven needs to put the rude duelist in the dirt.

The best part of this is always how it could have been avoided. Killing the Karthus would have tipped Fiora off to the teleport mischief, making it clear that the minion was not his target by disrupting the channel. But another way to check, one that is super under-used, would have been to click on the minion being teleported to. Doing that shows the owner of the teleport targeting the minion, which in this case was Riven, not Karthus.

So that's something to learn. The more important lesson here though, is why you shouldn't BM. You might get punished and become someone else's highlight.