Old as hell, but still awesome

[Bass Beatdown]

Won't the real Eggman please stand up?  

[Ennokni]

That's pretty great. What's the difference between Eggman and Robotnik?  

[Bass Beatdown]

I believe he was Robotnik in the American original Sonics, and he was always Eggman in Japan.  

[Mukuchina Kurasu]

Robotnic is Eggman't real name. Eggman is just a name sonic came up for him. If you Play sonic adventure, (the first game he is called Eggman) Sonic calls him that, but Robotnic calls himself Robotnic. But starting in SA2, he even calls himslef Eggman.  

[Meta_Fish]

Bongardo

Robotnic is Eggman't real name. Eggman is just a name sonic came up for him. If you Play sonic adventure, (the first game he is called Eggman) Sonic calls him that, but Robotnic calls himself Robotnic. But starting in SA2, he even calls himslef Eggman.

So he embraces the nickname to avoid being made fun of. Genius!  

[J of The Wind]

Dr. Ivo Robotnik.
Full name. True story.Check this. Found it musical and funny http://www.youtube.com/watch?v=Ezfotv37jBQ