Meaning of なってねェよ?

Question

What is the meaning of なってねェよ when used in this context:

Speaker A: 何すんだ！！コイツはおれの仲間になったんだ！！

Speaker B: なってねェよ！！！

Answer 1

Speaker B is saying that they have not become friends.

Speaker B: なってねェよ！！！

is

Speaker B: なっていないよ！！！

in more normal conjugation and spelling.　

For more on ねェ, see Clarification on 人の夢は終わらねェ , what does 言われなくちゃなんねェんだよ mean? ,