じゃな + Noun grammar


I currently playing a game and during the dialog a character says

> そんなワケない **じゃな** イカ! イカだけに!

What grammar concept is happening with じゃな + noun portion? Is it really just
だな + noun?

My best guess in translating is that they are saying

> That sort of thing is understandable, it's a squid! Given that it is a
> squid!




This そんなワケないじゃなイカ is "No way!" or "Nonsense!", but said with a pun.

The sentence is the same as そんなワケないじゃないか, which is a double-negative
rhetorical question that effectively means the same thing as the single
negative そんなワケない. (For this じゃないか, see
[this](https://japanese.stackexchange.com/a/1485/5010).) Here, イカ is in
katakana because it's a pun on イカ ("squid"). If you see "だけに" used like this,
it indicates the associated sentence is intended to be a pun. See: [How do
jokes with "だけに" work?](https://japanese.stackexchange.com/q/17389/5010)




This そんなワケないじゃなイカ is "No way!" or "Nonsense!", but said with a pun.

The sentence is the same as そんなワケないじゃないか, which is a double-negative
rhetorical question that effectively means the same thing as the single
negative そんなワケない. (For this じゃないか, see
[this](https://japanese.stackexchange.com/a/1485/5010).) Here, イカ is in
katakana because it's a pun on イカ ("squid"). If you see "だけに" used like this,
it indicates the associated sentence is intended to be a pun. See: [How do
jokes with "だけに" work?](https://japanese.stackexchange.com/q/17389/5010)

