It's a series of YouTube shorts (it may be on TikTok but I wouldn't know because I don't use it) made in Source Filmmaker (SFM), mostly using assets from Valve Software's Half Life 2.

The series features the eponymous Skibidi Toilets, which are human heads that are shown popping out of toilets and also sometimes urinals or bathtubs. The heads stare ominously at the camera and sing the Skibidi Toilet song with comedically and anatomically impossible (to a deliberately absurd degree) facial and neck animations.

From the Skibidi Toilet wiki:

The song is a sped-up remix/mashup of the songs "Give It To Me" by Timbaland (The most common and popular one), "Promiscuous" by Nelly Furtado and "Dom Dom Yes Yes" by Biser King.

The series starts out with a surrealist bent, with third-person omniscient cameras and swooping crane shots through sterile apartment and commercial buildings, usually panning to a Skibidi Toilet which sings its song before attacking the camera and the video ends. The first few videos are variations on this theme.

As the series goes on, it develops a more coherent storyline, showing giant Skibidi Toilets appearing in a human city and attacking the population, and the military attempting to fight back but being overrun.

Shortly, an army of humanoid robots with CCTV or sometimes movie cameras for heads (the Cameramen) appears and starts to do battle with the toilets. Whether they were created by humans or just arrived on Earth to fight the toilets from another world is not clear.

It's shown early on that the Skibidi Toilets can be defeated simply by flushing the toilet, which causes the head to comically spin before getting sucked down into the toilet, and this is the Cameramen's primary mode of attack. Physical damage to the head is also usually sufficient to incapacitate or kill the Skibidi Toilet, though the largest Skibidi Toilets are highly resistant to attack.

The series transitions to disconnected vingettes from the perspective of one of these Cameramen, showing their ongoing escalating war with the Skibidi Toilets. Larger and larger Skibidi Toilets with more advanced weaponry keep appearing, and the Cameramen build a large Cameraman Titan to fight them. Later, other factions of humanoid robots, the Speakermen and TV men, join the fight on the side of the Cameramen.

The series ebbs and flows, alternating between triumphant victory and devastating defeats for this Alliance. The episodes get longer (broken into multiple shorts to fit the format) and have more complex action.

We see that Skibidi Toilets have a hierarchy and use their song not only as a battle cry but also to communicate with each other. And later, the series shows them >!infighting which leads to a splinter faction appearing that is hostile to both them and the Alliance, with hints that these new toilets are even more dangerous as they have advanced weaponry and are able to speak English.!<

There's hints that the series is escalating toward an epic final showdown, but it's already had a few and I'm wondering where it's all going to end. That's why I say it's surprisingly engaging.