Different UserName

So I joined my 1.7.10 world and I got an achievement it might not be a bug but its weird... So I looked in chat my user name was DeadyDino but it said I was DeadyDino The Fat/ Smelly/Angry and I have no idea why please help I also changed my name to DeadlyDino112 but it just kept saying DeadyDino the angry fat weird ugly fat.