Clinging to sunken debris in shallow, marine mangrove forests in the French Caribbean, tiny thread-like organisms—perfectly visible to the naked eye—have earned the title of the largest bacteria ever known.

Measuring around a centimeter long, they are roughly the size and shape of a human eyelash, batting away the competition at 5,000 times the size of garden-variety bacteria and 50 times the size of bacteria previously considered giant. In human terms, this is akin to coming across a person as tall as Mount Everest.