Skibidi Toilet is a serious of SFM shorts that became popular with young kids. Think in the same vein as the weird flash videos or early SFM videos that were popular with young kids 10-15 years ago. “Skibidi” doesn’t mean anything and is just taken from that.
Source Filmmaker - basically the tech used in Valve’s games (IE Half Life 2, Team Fortress 2, Gmod) but repurposed into an easy to use animation tool. Valve used it quite a bit for their content but it was also popular among amateur animators since it was easy to use and had bunch of ready-to-use resources from Valve’s games.