Hux and Ren, unlikely friends, have similar but distinct taste in movies. Ren is a Star Wars fan, he cosplays and has his own Sith OC, while Hux has seen every movie by Mel Brooks multiple times, but his favorite is Spaceballs.

You know where I'm going with this, right?

Hux's favourite "nickname" for Ren in cosplay is Dark Helmet. At cons, photo shoots, while picking out materials, Hux ALWAYS calls Ren Dark Helmet when he has even the slightest excuse to do so. Ren never fails to throw a tantrum when he does this. It's amusing as fuck, so long as the property damaged isn't Hux's.

Can be slash, but vitriolic best buds works too.

++++ Ren gets him back by calling him Skroob.