Is NOBODY wrong in the post ? POST : This happened last Wednesday, we are 6 best friends (me and 5 others), one of them, let's call him (Z), didn't even wave when he saw us sitting together, and continued talking to a group of girls he was already sitting with, so we thought as a comeback, we'll just do a harmless joke(my idea), so we named our WhatsApp group "lonely bitch" then left, he tried calling later that day but we ignored him.

Next day, prank's over, we tried calling him to let him know that we are going Sushi later that week, but he didn't answer any of our calls or texts, eventually he did answer my texts and I told him it's a joke.

He started saying he kept crying that day, and that his old friends abandoned him and that we will never become the same again. He then asked me some really odd questions, such as if i regret introducing him to the others (as they liked him more) and if i was jealous and wanted to ruin it. Of course i denied that because that's simply not true, he himself is one of my closest friends. 

Now he's just being a dick and not answering any of our calls and messages, last message he sent was "I understand it's a joke, but I'll never be the same again with any of you" and "give me time". We made a new group and added him but he left..

I think he's overreacting to a harmless joke, i mean he also did mean jokes before and I never took them this seriously, but at the same time he appears to be very insecure towards this scenario.. 

I don't want to lose this dude, he's a good friend, but i was thinking of confronting him on Sunday and telling him how he's overreacting..

Am i the asshole? What should I do to reclaim this friendship? 

TL;DR: 
Named our WhatsApp group "lonely bitch" and then made all members leave except one as a joke, the guy took it seriously because of his insecurities and is really mad about it even after telling him that it's a joke. 