There's some rough news for Super Smash Bros. fans that were excited to see tournament play return. The Big House, one of the largest organizers for the franchise's competitive scene, had been planning an event for December, but Nintendo has issued a cease and desist to the organizers, adding to the list of Super Smash Bros. tournaments canceled this year.
While a number of Super Smash Bros. tournaments have been canceled throughout 2020 due to concerns about COVID-19, it seems as though The Big House's upcoming event was stopped because of how it was getting around the pandemic. According to The Big House's statement on the subject, the primary reason for the tournament being shut down is because of the use of a fan-developed project known as Slippi, which is essentially a third-party matchmaking tool.
The event itself was intended to be a celebration of Super Smash Bros. from Melee all the way to Ultimate, and in order to avoid creating a super-spreader event with the tournament, The Big House intended to host it entirely online. This is where issues begin to appear, however, because the online Super Smash Bros. Melee tournament required using Project Slippi in order to connect players in the normally offline title. It's unlikely that this specific issue would have occurred if the event had been safe to conduct in-person, as The Big House's past events had been, but the organizer cites this as the primary reason Nintendo struck the event down.
Slippi has been a target of Nintendo before, as the company is notoriously protective of its intellectual properties, especially ones as large as Super Smash Bros. Essentially, what Slippi does is it applies a series of mods to Super Smash Bros Melee that add a number of quality of life improvements to the game, as well as allows players to access a rollback netcode to open up online compatibilities. Since Slippi isn't an official project, and makes use of emulators like Dolphin to create a connection, Nintendo has frequently interfered with the use of the program.
Legally, Nintendo does have the right to ban the use of a program that it considers dangerous to its brand or IP, especially in the case of a tournament arranged by an outside organization. For this reason, The Big House will be complying with the orders as they have been presented. However, Nintendo has been coerced to roll back on these kinds of decisions in the past. If fans apply enough pressure to allow The Big House's Super Smash Bros. event to continue, possibly without the use of Slippi or the appearance of Melee, perhaps the tournament could go forward.
Super Smash Bros. Ultimate is available now for the Switch.