From a fish resembling a "cheeseburger with teeth" to a sea creature with a transparent head, several mysterious sea creatures were found in 2021, leaving experts and social media users around the world baffled.

Here is our list of five such alien-looking animals that were spotted in the past year.

Penis-shaped creature spotted in Australia

A free diver spotted a penis-shaped sea creature on the seabed off Rye Front Beach, Victoria, in February 2021. Her underwater camera managed to capture the creature that bore an uncanny resemblance to the male genitalia. Experts pointed out the creature was a type of unsegmented worm called priapulida.

Snake-like creature with huge jaw and sharp teeth

Nate Iszac was fishing in the Alaskan waters in March 2021 when he reeled in the snake-like creature, which was almost half the length of a grown man. The creature with a gigantic jaw and razor-sharp teeth was dubbed a "real-life sea monster" on social media.

Massive squid-like creature found by marine biologists

In October 2021, the scientists of the OceanX team were exploring a shipwreck when they spotted the creature swimming in the Red Sea, some 2,800 feet below the surface. The massive squid-like creature, which appeared to be larger than a human, was later identified as a purpleback flying squid.

Sea creature with 8 arms and 2 tentacles spotted

A team of researchers conducting an expedition in the Gulf of Mexico in November 2021 spotted the creature, which had a see-through translucent body, large fins, eight arms and a pair of tentacles. The animal, which was found nearly 7,820 feet beneath the ocean surface, was identified as a bigfin squid.

Sea creature resembling a "cheeseburger with teeth"

Roman Fedorov, a Russian fisherman, was working on a commercial fishing boat when he came across the creature. He quickly took a photo of it and shared it on social.

The photo went viral, with social media users comparing it to a cheeseburger or a Teenage Mutant Ninja Turtle.

The oceanic whitetip shark population has declined by 98 percent globally in the last half-century, experts warn
Ocean AFP / Andrea BERNARDI