Rizin FF has come and gone, there was some insanity there for sure, but there are always other New Year's Eve shows in Japan and one of those shows was Kyokugen. Kyokugen was a variety show on TBS in Japan that decided to throw together a dream fight. That dream fight was Masato vs. KID Yamamoto. Masato has been retired for a while now and KID Yamamoto is under contract to the UFC still, so the chances of them having an actual fight was slim-to-none.
Instead they had an exhibition, which was legal under KID's contract. KID, who has taken on quite a few new tattoos since his last appearance fighting on Japanese television, was forced to fight with a rash guard on due to Japan's broadcast laws against such yakuza-ish things. That being said, this still happened and damn is it cool to watch.