Nearing the halfway mark of a hard-fought (literally) scoreless game, Brad Marchand put the Bruins up by one, and then told the hostile Buffalo crowd to quiet down.
The Bruins-Sabres rivalry is one of the most intense in the modern NHL, and the fans in Buffalo had been letting the visiting team hear it all night long. There seemed to be very few players wearing Boston uniforms that weren't deemed boo-worthy by the crowd, so when Brad Marchand scored the first goal of the game he took the opportunity to send a message back to those fans.
His "shhh" gesture isn't going to help cool down this red-hot rivalry one bit - though it remains to be seen if the Sabres find it objectionable enough to send bloodthirsty sasquatch John Scott after Marchand.
No video of Buffalo fans responding to Marchand's gesture is currently available, but I wouldn't be surprised if they had a few finger gestures of their own to send his way.