With the Bruins holding a 3-0 lead in the second period, Marchand roped Carolina Hurricanes captain Justin Williams into a holding penalty after appearing to get away with a high stick. The Bruins All-Star proceeded to make a "C" with his fingers, holding it to his chest and appearing to taunt Williams for poor leadership.
Matt Grzelcyk scored the Bruins' second power-play goal of the game - and fourth of the series - with Williams in the box to extend the lead to 4-0.
Following the contest, Williams took full responsibility for his role in the incident.
"I've got to know better," the 37-year-old said, according to Fox Sports Carolina. "I'm old enough and I should be able to know better. I'm disappointed in general, absolutely."
The Hurricanes lost 6-2 and now face a 2-0 series deficit heading back to Carolina for Game 3 on Tuesday night.