The GoPro footage shot by pro surfer Kelly Slater in western Australia last week shows he might not have been alone in riding the wave.

About 17 seconds into the video taken while Slater was surfing the Margaret River region shows a shadow flick by his side. Was it a shark, a ray or Slater’s own shadow?

Image source: YouTube

Image source: YouTube

Image source: YouTube

Image source: YouTube

While many have said Slater was “sharkbombed,” an official has come out with what he thinks the shadow was.

“There was a actually a pod of dolphins in the area at the time, and Kelly actually got off the board and has essentially taken an underwater selfie with these dolphins,” Steve Robertson with the Association of Surfing Professionals told the Sydney Morning Herald, noting that other unreleased footage shows the dolphins. “There’s no doubt about it, it’s not a shark, it’s not a ray or another surfer, it’s actually a dolphin in the footage.”

But the issue isn’t quite settled with this comment.

Surfing WA chief executive Mark Lane told the Western Australian that he’s “100 percent” positive that the shadow is the reflection of another surfer.

“They would have probably been looking and watching, guys go through the tube and it’s quite common you’ll see a shadow in the wave,” he said. “[Slater] has continued to surf for another hour or so, if there had been a shark they would have been straight out of the water.”

Watch the footage posted on the Association of Surfing Professionals’ YouTube channel and judge for yourself:

(H/T: Daily Mail)