How do you make an entity like an enderdragon? [forge 1.7]

[Rapcat]

So far I have been successful at making a spawn egg and spawning the texture of a customised Steve which I made up - So far it is like this:

 

 

but how do you make a dragon for example - an Enderdragon

 

As I can only get the entity to be the same shape as Steve like in the pic above.

 

- If you need my entity render file or anything like that then just say.

 

[Eternaldoom]

Use a different model instead of ModelBiped.

[Rapcat]

thanks