This is a common problem with the cheap plastic dipsticks these days. Chrysler has the same problem. When I worked at Ford, I would use a vise grip adjusted just a hair smaller than the dipstick tube and clamp it below the dipstick. Emphasis on JUST A HAIR SMALLER, as you don't want to crush the dipstick tube. Then I would drill a small hole in the plastic, screw in a small screw, and pull it out with a needle nose pliers. Sometimes the plastic is too brittle and breaks apart, in which case you use a small pick and swear alot. This is not a big deal, dont't pull the oil pan or dipstick tube as I have seen suggested. It's just too much work for a minor problem. If you don't want to try, I'll bet any quick oil change place will have a resident expert that can remove it. As I said, this happens all the time.
