What started out as a relaxing family vacation day turned into a nightmare, and ultimately, a medical miracle of sorts.

Massachusetts resident Eugene Finney took his girlfriend and children to Huntington Beach, California in July as part of a family vacation. The weather was perfect and Finney was supervising his daughter playing in the ocean waves when he was slammed behind by something.

Finney told the San Jose Mercury News that it was the hardest he'd ever been hit in his life.

He struggled through the pain and shock to get himself and his daughter safely back to shore. His girlfriend pointed out the long gash on his back. Soon after, a crowd gathered near the water, and lifeguards were pulling everyone out of the water.

A shark sighting had been reported. The next day, a professional surfer was attacked by a great white shark and the beach was closed.

In the meantime, Finney was experiencing pain in his back, chest and abdomen. He didn’t seek immediate medical treatment, thinking he could just work through it. Finally, his boss convinced him he needed medical attention.

A series of tests were performed to determine his source of pain. Doctors concluded that his chest and back pain were due to blunt-force trauma, likely from the impact of the shark attack.

But doctors also discovered a tumor on his kidney, and it was likely malignant.

Fortunately for Finney, the cancer was detected early, at Stage I. The tumor was successfully removed with a minimally invasive procedure and most of his kidney was preserved. He is expected to make a full recovery and will not require radiation or chemotherapy treatments.

He was declared cancer-free Oct. 3, and has a shark to thank for sending him to the hospital at just the right time.