My Wylie got a paper grocery bag (the kind they have now with the handles) caught around his neck. He ran around totally freaked-out, and by the time I caught him, he had managed to tighten it up around his neck
Everything turned out okay, but the funny part was that he so scared my other kitty Kedi by running into him at top speed several times (and it made ALOT of noise), that Kedi ran upstairs and hid under the bed for a good hour. After that, he would not come downstairs for days because of the 'big brown monster' we called it.

Another danger: CANDLES My Kedi caught his tail on fire one time- luckely I was sitting right there to grab him and put it out!