An anti-bromance is the exact opposite of bromance in which 2 guys openly display hatred for each other often enjoying the abuse to the point it's almost sexual to them.
Troll: I hate that asshole
Asshole: I hate you too
Troll: FUUU OFFFF
Asshole: no YOU FUUU OFFF
RandomUser: you both argue everyday over the same BS, damn anti bromance and shit o.O