A sea slug from the Nudibranch family.

The sex life of a bizarre sea slug has become the subject of scientists’ attention after it was found to lose and regrow its penis after sex.

A study published in the Royal Society’s Biology Letters journal revealed that some species of sea slug grow a new sex organ after at least three sessions.

Conducted by Japanese researchers, the study looked closely at the copulation habits of sea slugs that had been captured in the Pacific Ocean. Their findings proved shocking to the scientific community, which has never seen anything like this before.

“No other animal is known to repeatedly copulate using such disposable penises,” the researchers said. They added: “We propose that the tissue at the spiral part of the penis is compressed and undifferentiated, gradually differentiating into the next penis. It may need approximately a day for the spiral structure to be ready for copulation.”

Almost all sea slugs are thought to be simultaneous hermaphrodites, which means that they are equipped with both female and male sexual organs and are able to use them both at the same time.