The serpent was inside Eve.
It's that thought process that a person goes through when they consider sinning vs. not sinning, and convince themselves that "it won't hurt anything"
Scapegoating.
Excusing one's self from responsibility.
Blaming one's transgressions on a literal snake or external Satan, instead of taking accountability.
This is the type of reasoning that True Christians need to avoid, the above reasoning is not Gods thoughts but man's, there is no scriptural basis for such a belief that the serpent was inside Eve.
The Bible makes it quite clear that Satan was the one in control of the Serpent, these are not my thoughts but Gods;
(Revelation 12:9) "...So down the great dragon was hurled, the original serpent, the one called Devil and Satan, who is misleading the entire inhabited earth..."
As we can see from the above verse Satan
was the original serpent, it wasn't Eve's invisible qualities as enoch1nine wrongly stated. Satan is a real person, he in not an abstract force.
Mo0448, regarding your original question, yes it would of been unusual for any animals to talk, to which wouldv'e been to Eve's shock. However what you need to remember is that Genesis doesn't add all the fine details to its stories, hence you get questions such as your own.
The Bible characterizes Satan’s tactics as “machinations,” or “crafty acts,” and this incident helps to prove the point. What we see in Eden is no fable about a talking animal; it is a chilling example of Satans clever strategy designed to lure people away from God. What I like to think happened during man's fall into sin is this, (please remember this is all speculative).
Satan using his supernatural powers and deceptive thinking patiently waited for Eve, the less experienced of the two humans, to walk past by the tree of Knowledge of Good and Bad which may of been her custom during that certain part of the day. Satan then through the Snake began eating the Fruit of the tree (The snake eating the fruit or
even Eve eating the Fruit was not punishable by God, Gods command was that only Adam wasn't to eat off the Tree, hence it was only when Adam ate the fruit that both his and Eve's eyes were opened)
(Genesis 3:6, 7) "...So she began taking of its fruit and eating it. Afterward she gave some also to her husband when with her and he began eating it. Then the eyes of both of them became opened and they began to realize that they were naked. Hence they sewed fig leaves together and made loin coverings for themselves..."
When Eve caught sight of what appeared to be a simple serpent on the tree she would of been shocked, since she herself believed that simply touching the tree would kill her, so when she walked abit closer and not only was the serpent on the Tree but eating its fruits she would of been completely perplexed. This is when Satan cleverness and craftyness shines brightest, he makes the serpent speak. When eve heared this she could of been frightened and shocked, she then might of told the snake it wasn't allowed to eat the fruit with him saying;
“Is it really so that God said YOU must not eat from every tree of the garden?” as we can see from Genesis she replies
‘YOU must not eat from it, no, YOU must not touch it that YOU do not die.’” Then Satan craftily puts the thought in Eve's heart by saying
“YOU positively will not die. YOU are bound to be like God, KNOWING good and bad."
Now think, If Eve was newly created by God, maybe only a couple of months/years old (Created with a Mature adult mind and body of course) with her naivety she might of thought "God has said we can't eat from the tree or we'll Die but yet this snake which is and animal, which can't even talk has eaten it and has become wise and also hasn't died, and telling me I won't die but will become like God knowing Good and Bad" This then led to Eve eating the Fruit, however when she ate the Fruit nothing happened, she didn't die, she wouldv'e suffered no benefit or drawbacks. When nothing happened she then went to Adam and possibly told him everything that happened, that a speechless animal ate the fruit and gained knowledge and didn't die, however with his wisdom and maturity he gave into temptation
for his wife, he however wasn't deceived by Satan tricks.
(1 Timothy 2:14) "...Also, Adam was not deceived, but the woman was thoroughly deceived..."
This how I think it went down, I might even be correct, but I also might be wrong. We just have to keep remembering that the Bible doesn't always go down into the nitty gritty detail, sometimes it does but at other times it just tells you whats necessary. When you think about it Genesis chapters 1-3 tells the story from the Worlds creation to mans fall, Moses could of wrote a Bible sized description of the worlds creation to mans fall into sin and it still wouldn't of covered everything.
Hope you find this interesting.