They are called "unicorns of the sea" and they are infesting the Pacific Coast, destroying fishing nets and puzzling scientists, the Guardian reports. The tiny blob-like creatures are infesting some stretches of the West Coast as far north as Alaska so badly that fishermen can't catch anything. The translucent tubular invaders are pyrosomes, and while they generally range in size from a few inches to 2 feet, they band together in huge colonies. (See video.) They rip nets and clog hooks, and wash up on beaches to the consternation of the locals. One researcher began spotting the "sea pickles" in nets in February and since then, the numbers have exploded, per Oregon Public Broadcasting. One research boat captured 60,000 within minutes.
"They were glowing and floating on the surface, completely covering the sea," says University of Oregon researcher Hilarie Sorensen. The creatures—their Greek name means "fire bodies"—prefer the tropics, but even there, they haven't been seen in the "insane" numbers of this year's bloom, says Sorensen. The impact of the little cucumbers is unknown, but there is concern their massive presence could foul ecosystems. While the bloom could be a natural phenomenon, Dr. Lisa-ann Gershwin says "an abundance this gobsmackingly big" indicates something fishy may be going on. Warming seas could be a possible explainer, or perhaps changes in the marine food supply or shifting currents. (Killer whales are also tormenting Alaskan fishermen.)