My son watches this show and all the media that’s based on it, there’s alot of bandwagon youtube stuff that people have jumped on just to get those all-important views. I try to understand what my kids are into, so I sat down and actually watched all 60+ episodes of it that were out at the time.
As others have explained, it basically started as a video made with Source Filmmaker that uses assets/characters from Half-life. Alot of it is non-sensical, but there’s some sort of invading force of skibidi toilets (toilets with heads popping out that sing the skibidi song) that are apparently attacking this world. There seems to be regular people there sometimes in earlier episodes, but mostly you see Camera Men (literally just people with videocameras for heads) that are fighting back in some sort of forever war.
As the series progresses, new characters, skibidis, and electronics people are added to the roster, it’s a sort of constant one-upsmanship between the two powers, almost akin to GI Joe or Transformers, but weirder. So you start seeing SpeakerMan, TVMan, and even -Woman, and -Titan versions of all these, but then the Skibidis too come up with new weapons or variants in the war.
And that’s the basic gist of it, though the lore just keeps getting built up over time and keeps getting progressively weirder. My son gets obsessed with it and the music is annoying as hell, I hadn’t heard the skibidi song before, but it’s apparently a remix of something. The electronics people also play a Tears for Fear song (“Everybody wants to rule the world”).