What is it, you might ask? It's easy: Wyoming plans to sue states that don't buy coal. It's just as stupid as it sounds. Wyoming has decided that rather than admit that coal as a whole is dying and making the painful but necessary long term move of moving away from coal and developing new industries in the state to replace it, they are going to just burn money on frivolous lawsuits to try and prop up an industry that is going to die no matter what they do.
That's not even getting into the question of whether they have any sort of legal standing to sue over something like this to begin with.