It really is the end of an era: Zayn Malik just slammed Louis Tomlinson on Twitter.

After Louis and Naughty Boy got into it on the social media site yet again (more on that below), Zayn lashed out at his former bestie in one seriously harsh tweet:

Whoa. While we try and process the fact that Zayn is actually blatantly (and publicly) dissing someone who he once was so close with that the two got high together in the back of a van in Peru, let's figure out how we got here. Of course, it all started with a provoking tweet from producer Naughty Boy, who has been a constant fixture on Zayn's arm since he quit One Direction back in March.

Naughty Boy tweeted a photo of himself with Zayn, captioning the pic, "Replace this."

While it wasn't a direct hit at 1D, it definitely could've been interpreted as such. In any case, it's a tweet that will no doubt enrage hardcore Directioners -- and Louis himself, who had no problem going after the photo's filter:

Of course, just a few minutes after Louis' tweet fans immediately began trending #TOMLINSONSLAYSAGAIN. (No surprise there.)

Still, Naughty Boy hit back -- and hard, dissing Louis' vocal ability. Yikes.

And then they went a little back and forth:

And then Zayn's tweet to Louis happened, which immediately stopped everyone in their tracks (R.I.P. #ZOUIS).

Seriously though, we hope that Louis and Zayn resolve this fight ASAP -- because our hearts can't take the lack of Zouis friendship. We need it in our lives now and forever.