A Globster, or Blob, is an unidentified organic mass that washed up on the shoreline of an ocean or other body of water. The term was coined by Ivan T. Sanderson in 1962 to describe the Tasmanian carcass of 1960, which was said to have "no visible eyes, no defined head, and no apparent bone structure". A globster is distinguished from a normal beached carcass by being hard to identify, at least by initial untrained observers, and by creating controversy as to its identity. Globsters are most frequently studied in the field of cryptozoology.
Globsters may present such a puzzling appearance that their nature remains controversial even after being officially identified by scientists. Some globsters lack bones or other recognizable structures, while others may have bones, tentacles, flippers, eyes or other features that can help narrow down the possible species. In the past these were often described as sea monsters, and myths and legends about such monsters may often have started with the appearance of a globster.