Answer: obscure and mysterious.
Explanation: The connotation of a word is the meaning given by the context or even by the readers (or listeners) based on their emotions or personal experiences. In the given excerpt from "Animal Farm" we can see the reaction of Benjamin the donkey to the Rebellion. In this excerpt, the connotation of the word "cryptic" is "obscure and mysterious," as Benjamin doesn't really give his opinion by saying "Donkeys live a long time. None of you has ever seen a dead donkey."