At first, people thought the famous “Duckbill” rock formation at Cape Kiwanda State Natural Area had died a natural death. It’s made up of delicate sandstone, after all, and the popular selfie spot along the Oregon coastline is under constant attack from Mother Nature.

But someone was filming when the rock lost its battle with gravity in late August. The video does not lie: Duckbill’s demise was intentional.

“All eight of them got it to wobble; then five of them backed off and the other three just kept going, kept going, kept pushing,” said David Kalas, who recorded video of the unidentified vandals’ assault on the rock and sent it to several TV stations, including ABC affiliate KATU.

“I saw them actually topple the rock over,” Kalas told the news station. “And they were just standing on top of the rubble of the rock, just like laughing, like smiling, just giggling.”

On Sept. 1, the Oregon State Parks Facebook page shared before and after photos of the rock formation with a caption highlighting the fragility of coastal formations and cliffs.

“So this happened,” the caption read. “The iconic sandstone formation at #CapeKiwanda — some called it the Duckbill — has collapsed. No one was injured, fortunately; but the rubble serves as a sobering reminder of the ever present dangers of our fragile coastal rocks and cliffs. Who knows what will collapse next? #gravitywins #besafe.”

The caption noted that the photo showing Duckbill still standing, with a couple standing atop its flat surface, was “a ‘before shot,’ ” adding: “The people on the rock were not present when it collapsed.”

But the department’s tone changed after the video emerged, showing the formation’s not-so-natural collapse, at the hands of another group of humans.

“At the time it was discovered, there was no sign the formation had been vandalized,” OPRD said in a news release Monday. “Since then, media in Oregon have obtained a video apparently showing a group of visitors pushing the formation to the ground.”

The agency said it would work with Oregon State Police to “review the incident immediately and decide how best to respond,” adding, “The department takes vandalism of a state park’s natural features seriously.”

The rock formation is fenced off, in part because it’s in a dangerous area: Six people have died there in the past two years, and several others have been injured, according to the Statesman Journal.

The fine for damaging the natural feature could be as high as $435, Oregon Parks and Recreation Department spokesman Chris Havel told the Statesman Journal.

Kalas, who recorded the moment Duckbill died, told KATU that he was visiting the park in Tillamook County, near the northwest tip of the state, to experiment with a new drone camera.

Images of the sandstone pedestal actually show up in some of his footage; he’s one of countless people to snap a picture of the formation, which was between seven and 10 feet wide at the top.

But at some point, Kalas said, he heard people yelling near the rock and saw as many as eight men pushing on the rock formation.

Authorities hadn’t released the names of any suspects or announced any arrests by Tuesday morning.

People learning of the rock toppling, however, had harsh words for the vandals — and fond remembrances for the formation — on social media.

Read more: