They’ve been known for decades but not much is known about them:
There are two main schools of thought regarding the blobs, according to Quanta. The first camp holds that they’re merely massive clusters of hot plumes. The other argues that the blobs — so big that they would drown the planet’s surface in a lava ocean over 60 miles deep — are their own distinct entity and not just a particularly warm region of the core.
Dan Robitzski , “ Geologists baffled by “massive anomalies” at edge of earth’s core ” at Futurism.com
At Quanta, it’s suggested they might be linked to extinction events:
According to studies led by Trond Torsvik at the University of Oslo, the blobs also seem be linked to about two dozen surface regions called large igneous provinces — places where, at multiple times in Earth’s past, millions of cubic kilometers of lava oozed onto the surface as if through open wounds. Many of these events are themselves linked to mass extinctions like the Great Dying, the largest life-snuffing episode of the last half-billion years.
If that correlation isn’t a coincidence, Lekić speculates that these events could even be the result of blobettes calving off the main structures. If buoyed to the surface, they would be rock-meltingly hot enough to cause those gigantic, sustained eruptions. In turn, that volcanism could have changed the climate and even led to mass extinctions. Such a sequence, if verified, would be the ultimate antediluvian time bomb — apocalyptic extinctions triggered by subterranean structures buried since the birth of the world.
Joshua Sokol, “Continents of the Underworld Come Into Focus” at Quanta
This would make a great backdrop for a sci-fi novel, later optioned as a film.
The general idea:
https://www.youtube.com/watch?v=Cuy2A7UcHm4