This strange creature gently roaming the sea floor thousands of feet under the surface of the ocean is a giant sea spider (Colossendeis sp.) It's called "giant" because it's larger than a dinner plate and can grow up to 20 inches (50 cm) wide. Oh, and it's called a "sea spider" because it is actually related to the spiders we find on land.
Sea spider, or pycnogonids, come in a variety of sizes and appearance. Unlike land spiders that spin webs to trap their prey, sea spiders use a tube-like proboscis to "slurp" up its food. They're "suctorial" predators, meaning that most sea spider species feed by sucking the bodily fluids out of their prey (often anemones).
Researchers from the Monterey Bay Aquarium Research Institute captured an image of this brilliant red sea spider walking around when they explored an area around a sunken whale carcasses on the deep seafloor.
Image: MBARI