A strange, snake-like image appeared on weather radar in the ocean off the coast of Australia near Rottnest Island Wednesday, baffling meteorologists. Theories as to what could cause such a phenomenon swirled. But now the government is coming forward with an explanation.

This radar image shows the "Rottnest Monster," which was later determined to be the work of a military exercise. (Image source: Bureau of Meteorology via ABC News)

Neil Bennett with Australia's Bureau of Meteorology told ABC News he ruled out the S shape being caused by a cloud or rain echo.

"They don't take on S shapes and things like that," he said.

With meteorological causes debunked, some went as far to speculate that it could be a giant sea creature, dubbing it the "Rottnest Monster" or "Rottness Monster," a play off of the Loch Ness monster.

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So what is it?

Thursday a defense spokesman answered inquiries, saying the shape was caused by a training exercise that involved ships and aircraft, The Guardian reported.

A MODIS satellite image of the area where the "Rottnest Monster" was spotted Wednesday. (Image source: MODIS via@weather_wa/Twitter)

The exercise was “designed to prepare a navy warship for an operations deployment," the spokesman said, adding that "environmental conditions over the West Australian coast at the time of the activity provided a unique opportunity for this routine activity to be visible on the weather radar display."

Some are saddened -- albeit jokingly -- that it wasn't a sea monster.

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Before the military officially came forward to note its involvement, some on Twitter pointed out that flight radar showed a Learjet flying over the area around the time the strange formation was spotted.

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According to ABC News, the defense spokesman said the activity is ongoing.

(H/T: Gawker)