If there's one man in the NFL with a reputation for being a bit of a killjoy, it's Bill Belichick.The New England Patriots head coach certainly knows how to ruin the fun that opposition teams are having on the pitch. Since becoming the Patriots HC in 2000, he has had more success than anyone else, winning five Super Bowls. Recently though, there's been a lot of drama off the pitch and the dynasty that Belichick helped build may finally be starting to fall. He's come under fire for letting five key offensive players leave already in the off-season and even one of his current stars, Rob Gronkowski, has suggested that he's not having fun anymore. NBC Sports Tom Curran reported back in March that the tight end felt “persecuted” and “singled out” last year, leading to him considering retirement.Even more recently, Curran has suggested that now it's Tom Brady who's leading a "pushback" against Belichick and the culture surrounding the Patriots. With preparations for the 2018 season well underway, things appear to be far from good for the team that has dominated the AFC for almost two decades.  Although it may be tough now, recently, a video has emerged from back when times were happier in New England - and it should put a smile on any Patriot fans face. An old video, shared by The Checkdown, shows former Pats wide receiver Randy Moss having a conversation with Belichick. He tries to convince his coach to attend a Halloween party - but it's not just any old party. Moss explains that he's hosting it at a roller rink, and everybody that's going is dressing up. Is there anything that sounds further from the idea of fun for Belichick? Probably not. But incredibly, he actually turned up, dressed as a pirate. Yes. Bill Belichick, dressed as a pirate, was once filmed rollerblading around at a Halloween party. Check it out below.

Amazing.

Unsurprisingly, most fans weren't too sure how to react to the video. Actually, it's just a shame it's taken so long for the clip to surface. 

Judging by the whispers coming out of New England now though, it's unlikely that Belichick will be attending any party thrown by his players this year. 

You never know though, the head coach that portrays a persona of a man that doesn't like to have fun could actually be a secret party animal. Then again, maybe not.