Tourists on the deck of a cage-diving boat were surprised when a great white shark emerged from under the boat swimming upside down in a rare encounter in South Australia.

Wendy Bower-Leech, who was among the tourists with Calypso Star Charters out of Port Lincoln, captured the moment in video earlier this month and shared it Thursday with the cage-diving company.

“We do not see them do this very often at all,” the charter company wrote in its post. “In fact, it was the first time Captain Dave [Clayfield] had seen it himself.”

In the video, a passenger can be heard asking, “Is that normal?”

“No,” another replies.

“I’ve never seen a shark do that before,” a guide says.

Some have erroneously reported that the behavior is called tonic immobility, but this shark is not immobile. Tonic immobility occurs when a shark goes into a trance-like state by a reflex that causes a temporary state of inactivity, according to Shark Trust.

Also on FTW Outdoors: 17-foot great white shark shakes cage full of divers

Calypso Star Charters is touted as the only place one can cage dive with great white sharks in Australia. It is fully licensed by the Department of Environment and Water.

But you don’t always need to be in a cage to witness memorable encounters with great white sharks, as this video proves.

Photo courtesy of Calypso Star Charters.

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