I don't see what's irrational about saying "there's no conceivable way the antlers could have evolved." Now, in point of fact, I disagree with Faith, but how is saying that a fallacy?
It's irrational because she doesn't give any kind of reason to PROVE that it was impossible. She expects her opinion on the matter to carry the weight of fact.
Saying "There is no conceivable way that the Earth holds me down with some invisible field called gravity which is a property of all mass," does not cause me to float away from the Earth. Another example of this would be, "1+1=2! That's the most ridiculous thing I have ever heard!"
Just becuase she doesn't understand it or accept the evidence doesn't make it not true. Technically this is an
Appeal to Ridicule fallacy.