There are some people who are speculating about that one episode wherein Bart dies. This is considered to be a lost Simpsons episode which means that it was not actually shown to the general public. Fox actually has an inconsistent way of counting episodes so even if you would try to trace this particular episode, it may be a bit complicated to find.
Some say that this episode contains the dates of the people who became guests on the television series. It showed when they would die. People say that this lost episode is not something that the makers of the show would like to talk about. Dead Bart is still the person who plays Bart in the series.