Throughout Tanach and Talmud, there are numerous recorded uses and practitioners of magic1.
From Pharaoh's magicians to Shaul's necromancer, and magic cucumbers to were-donkeys, the references are numerous. These are not only brought as stories, but oftentimes as factors in halacha.
My question is, why don't we see magic practiced today? Does it still exist? Is it still theoretically do-able or has "nature changed"? If it's no longer possible, when did this change occur?
1: (When I say "magic", I refer to supernatural powers that stem from the forces of impurity in the world. Commonly referred to as "sorcery" or "'black' magic", it was used to do things that are naturally impossible, such as necromancy, transforming objects into other objects, and "creating" things (as long as they're larger than a barley-corn (I think that's the measurement, right?)). Frequently "sheidim" (demons) and their powers were employed in the use of magic. Not to be confused with illusions and illusionists.)