Or, as the motion describes them, the "World Champion Dallas Mavericks."
Assuming this describes the case correctly – and it does appear to be a real filing, although whether it's a real motion for summary judgment or just gloating is hard to say – the Mavericks' management was sued by a shareholder claiming that the current owner has mismanaged the team. Noting that the team has just won the NBA championship, the motion suggests that the plaintiff's case lacks merit.
There are no exhibits attached to the motion, but it does contain one very large picture of the team celebrating its championship.
According to the docket, a jury trial is set for October 3, but it seems like this is a case that might more-or-less quietly go away.