It should be called a UUO — unidentified underwater object
Well, it’s ovoid, bifurcated and apparently fragments at right angles, which says it’s not a naturally occurring structure. The images I saw looked to be stone or stonelike, unless that was sediment atop some other material. The “path” looks an awful lot like it skidded to rest where it is, could be manmade too, I suppose, assuming this site was submerged later, after it was created, for whatever purpose.
It is a puzzle.