Now you see it.
Now you don't.
The test bombing is apparently meant to show that the bomber (a GBU-10 bomb dropped by a B-1) can be effectively deployed against small sea-borne surface targets, such as pirates, or other small moving objects.
A single GBU-10 bomb costs $23,700. The weapon was developed in the 1980s for the USA's Cold War needs, but was not used until 1998, when President Clinton issued a military strike in Iraq.