Free diver Josie Jones, 48, was scouring the waters around Rye Front Beach in Victoria when she came across the bizarre marine worm.
Obviously, you can see where it gets that unique moniker from, because it really does look like a weird willy, doesn't it?
To be fair, it's actually called a priapulida in scientific terms, but penis fish is a lot more fun.
Josie was naturally quite amused by her discovery, as were those who later saw it on social media.
After she uploaded the images from her underwater camera, one person commented: "Wow some marine animals are going to have fun with that."
Josie responded: "You've got such a wonderful imagination."
Another person said: "It made my day and some of my friend's [sic] day too."
