A better choice would have been "a different" rather than "another" snake.
That is an another snake. Is that wrong?
Yep, that sounds really wrong to me - i think an another can't go together despite the rules assuming it can..but a another sounds okay (leaving the article off completely sounds WAY more natural though...).
And a another sounds horrible here still - i just meant in some sentences it can sound okay
Yes. Another is an + other in English. An another is redundant and poor grammar.