The incredible incident occurred recently in the Strait of Magellan off the coast of Chile.
For kayaker Adrian Simancas, it had been an adventure of a lifetime - but little did he know that within seconds, he would find himself inside the mouth of a gargantuan ocean-borne mammal.
The incident, which was captured on camera by Adrian's own father who was filming nearby, saw a huge humpback whale suddenly emerge from the water directly beneath him, engulfing both he and his kayak in one fluid motion.
"I thought I was dead," Adrian told the Associated Press.
"I thought it had eaten me, that it had swallowed me."
For a brief second his father looked on in horror, until - as quickly as it had begun - the incident ended with Adrian being released back into the water by the creature.
Fortunately, he hadn't suffered any injuries, but the freezing water was still a major concern.
"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," he recalled.
As luck would have it, however, they were both able to make it back to shore in one piece.
You can check out the video of the incident below.