A mistrial is basically when a trial gets cancelled or halted because something has gone terribly wrong. It's like when you're baking a cake and you realize you've added twice the amount of salt - you just have to start over. In the case of a trial, it means that the whole thing has to be restarted from scratch, which can be a real bummer for everyone involved.
But don't worry, it's not the end of the world - in fact, mistrials are more common than you think. It's estimated that up to 10% of trials in the US end in a mistrial, which is a pretty staggering number if you ask me. And the reasons for a mistrial can vary from juror misconduct to new evidence that comes to light during the trial.
