A monster from the deep has shocked beach-goers after it washed up at Muriwai Beach.

Melissa Doubleday posted a photo of the mysterious object to the Muriwai and Waimauku Area Community Group Facebook page, asking "if anyone knows what this is??!".

Facebook commenters then dug deep into their collective knowledge to speculate on what the object could be, with suggestions including a shipwreck, a piece of art, a Carribean walrus and a Rastafarian whale.

The object is actually a huge bit of driftwood, and is covered in what appear to be gooseneck barnacles.