I was wondering how long it would take for an arm swiped off of a recently murdered victim to start to rot away. I thought the whole prosthetic arm from a dead body thing was hillarious especially when they went out dancing and she had that motionless dead left arm lol. Anyways later in the courthouse she has that same arm although I imagine this was several days later and the arm looks the same. She is crazy though maybe she killed some other woman and got herself a fresh one.
Well, I may be wrong (it's not like it would be a first, lol), but I doubt it, since this is one of my favorite films and I've probably watched it close to 50 times...and I know this might lower your view of the whole picture, unfortunately, but...
That isn't a "prosthetic arm from a dead body," it's a real, genuine prosthetic arm (don't ask me where she got it, doesn't matter, anyway). The point wasn't that she was trying to replace her arm, it's that she was trying to leave her arm with the corpse so it would be identified as her (again, don't ask me about the remaining one, except that maybe she was careful about how she burned the corpse).
At least that's the way it always looked to me.
(Here's a better question, something that I've always seen as something of a gaping hole: after his nightmare, Jack goes to "visit the boys." Next time we see him with Natalie, which doesn't seem like all that much later, perhaps the very next night, he's making up with her for something. For what? Looking in on his squad? There's really been no other indication of an argument or anything up to that time, yet they're both clearly upset. Was something cut from the film?)
Well then that was one spooky looking wretched prosthetic arm. Here is another hot one...If she wanted to fake her death and all this other nonsense only to kill the mafia don a few days later and take over his operation and then go about her business with the same face and name in public it doesn't make a lot of sense. Why not just kill who she wants...take over their operation...and do all of this without maiming herself? Well the only explanation for this is perhaps she is just plain insane and likes doing morbid things to herself and others
Okay, first off you must remember (though it was only glanced at for a moment in flashback) that she had been arrested for killing the feds holding the Dennis Farina character; at the same time the Don told Jack to kill her for fear that she'd turn evidence against him.
She wanted proof of her death to get the cops off her case (she'd already bribed Jack to get her the necessary paperwork). Switching the arms would give the cops her "body." (We have to assume that the fire was lit so as to not damage that arm!) If you look close, you see that, not only does she remove the one arm, but she replaces it with her own.
And she knew that she posed a threat to the Don now, and that he wouldn't stop until he'd killed her, that's why she killed him. There's no indication that I remember of her ever expecting to "take over." (In fact, at some point around that time she's agreed to cut a deal with the cops instead and turn over Jack.)
As for "maiming herself"...she didn't. During the struggle in the car (when she tried to strangle Jack) she was shot in the arm, and evidently lost the use of it then. Using the loss of your arm to fake your death is an ultimate example of making your lemons into lemonade!