Winger Matthew Tkachuk got a little reckless in the Calgary Flames' game against the Edmonton Oilers when he laid a vicious check from behind on Zack Kassian. That, however, was the civil part of the interaction, because Kassian turned around and absolutely pummeled the daylights Tkachuk.
This was not a fight. It was an absolute beating. Kassian wasted no time seeking out Tkachuk before delivering a series of massive blows to his head, despite getting cracked extremely hard into the boards.
Tkachuk is definitely going to think twice before going in on Kassian like that again in the future ... and so will every other NHL player.