Unidentified submerged object

Unusual phenomenon in water that is not readily identifiable

An unidentified submerged object (USO) is an unidentified object submerged in water. The U.S. Navy classifies USOs as whales, sharks, and other sea creatures that can interfere with ship maneuvering, sonar operations, and oceanographic research. Though the term has also been used to refer to alleged unidentified flying objects (UFOs) which can both fly and travel through water.

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