That name... was never found.
When the ULF system came around, it became known as ULF 2, and was the only Metroid II enemy in that list. Eventually, ULF 1 found a name. But never ULF 2. Its name has never been found ever. It eventually became the icon of ULFs everywhere.
In honor of its lack of a name, and of its bizarre behavior, I give it the name, Bob.