A humpback whale briefly swallowed a kayaker off Chilean Patagonia before quickly releasing him unharmed. The incident, caught on camera, quickly went viral.

Last Saturday, Adrián Simancas was kayaking with his father, Dell, in Bahía El Águila near the San Isidro Lighthouse in the Strait of Magellan when a humpback whale surfaced, engulfing Adrián and his yellow kayak for a few seconds before letting him go.

Dell, just meters (yards) away, captured the moment on video while encouraging his son to stay calm.

"Stay calm, stay calm," he can be heard saying after his son was released from the whale's mouth.

"I thought I was dead," Adrián told The Associated Press. "I thought it had eaten me, that it had swallowed me."

He described the "terror" of those few seconds and explained that his real fear set in only after resurfacing, fearing that the huge animal would hurt his father or that he would perish in the frigid waters.

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Despite the terrifying experience, Dell remained focused, filming and reassuring his son while grappling with his own worry.

"When I came up and started floating, I was scared that something might happen to my father too, that we wouldn't reach the shore in time, or that I would get hypothermia," Adrián said.

After a few seconds in the water, Adrián managed to reach his father's kayak and was quickly assisted. Despite the scare, both returned to shore uninjured.

Located about 1,600 miles (3,000 kilometers) south of Santiago, Chile's capital, the Strait of Magellan is a major tourist attraction in the Chilean Patagonia, known for adventure activities.

Its frigid waters pose a challenge for sailors, swimmers and explorers who attempt to cross it in different ways.

Although it's summer in the Southern Hemisphere, temperatures in the region remain cool, with minimums dropping to 39 degrees Fahrenheit (4 degrees Celsius) and highs rarely exceeding 68 degrees Fahrenheit (20 degrees Celsius.)

While whale attacks on humans are extremely rare in Chilean waters, whale deaths from collisions with cargo ships have increased in recent years, and strandings have become a recurring issue in the last decade.