During today's Bruins versus Avalanche game it appeared that Avalanche forward Nathan MacKinnon
intentionally slashed a linesman after a face off. This sort of action is against NHL Rule 40 and could result in an up to 20 game suspension.
At the end of the video you can clearly see the linesman turn to MacKinnon, but it is difficult to prove intent in this situation, but it does look like MacKinnon aimed for the linesman. The NHL Rule reads as follows:
40.2 Automatic Suspension - Category I: Any player that injures or tries to injure an official gets a minimum of 20 games. The rulebook defines "intent to injure" as "any physical force which a player knew or should have known could reasonably be expected to cause injury." So if anyone tried to pull a Chris Simon on an official, he can't then claim, "I didn't know it could hurt him like that." Actually, he can, but his claim won't be taken seriously.
40.3 Automatic Suspension - Category II: This rule subset outlines a lighter punishment if a player applies physical force "without intent to injure." It also includes a provision against spitting on an official. Violations under this rule incur a minimum 10-game suspension.
40.4 Automatic Suspension - Category III: A longer list of offenses—including physicially demeaning, physically threatening, spitting at (as opposed to on) an official, or physically forcing himself free from an official—incurs an even lighter 3-game suspension minimum.
According to this definition of the rule this incident would likely fall under either Rule 40.2 or Rule 40.3 which would issue an automatic 10 or 20 game suspension.