The U.S gov and maybe others do have underwater craft. (Explains “some” USOs)

Iam not saying that all USO cases are from world government secret programs because I have seen no sings of craft going in and out of the water, but governments definitely have secret programs with tech we can’t even fanthom. Here is a example of a new DARPA underwater unmanned craft. Who knows what the U.S has been making in the last 5p years.