The Boston Celtics and Washington Wizards do not like each other. 

They got into multiple scuffles during the regular season, both during and after games, with Jae Crowder even bopping John Wall right on the nose after one of them. Al Horford and Markieff Morris are now sworn enemies after their incidents this series. The Kelly vs. Kelly duel between Oubre and Olynyk has resulted in ejections and NSFW chants. Avery Bradley even said he would beat up Marcin Gortat. As Isaiah Thomas put it after Game 3, "we don't like them, and they don't like us." 

Now, ahead of Game 6 on Friday night, another layer has been added to the ever-growing feud. 

The Celtics, up 3-2, and with a chance to close out the series in D.C., showed up in all black. The stunt has become fairly commonplace over the past few years, as a way to signify that the team leading the series is showing up to a funeral for the team they're about to eliminate. 

The trend (at least as far as I can tell) was actually started against the Celtics back in 2013, when the Knicks wore all black to Game 5 of the team's first-round series. Of course, being the Knicks, they actually lost that game -- though they did go on to win the series. 

With their history this season, it should come as no surprise that there's more to the Celtics wearing all black than just letting the Wizards know they think the series is going to be over. Back in January, the Wizards showed up to a regular season game between these two teams rocking all black outfits, a move Isaiah Thomas called, "cute."

Now, with a chance to eliminate the Wizards on their home floor, the Celtics are mockingly doing the same. I mean, there's always the possibility the whole team just turned goth since Game 5 ended, but I think it's more likely they're just trying to mess with the Wizards.

Well, most of them at least. Apparently Al Horford did not get the memo, as he showed up in a beige sweater that was just somewhat covered by a black vest. 

Also, Celtics co-owner Wyc Grousbeck would like people to know he is not part of the scheme, he just wears black a lot.

This is kind of funny, but the Celtics absolutely have to win this game now. 

You really can't show up to another team's gym in all black to mock them and then lose the game. You just can't do it. Well, not unless you're okay with facing an unending stream of jokes and criticism afterwards.