They said later it appeared to them that it was ready to fall and might hurt someone.
In the video, posted on Facebook, one man can be seen leveraging himself against a nearby rock and pushing a formation over.
"Some little kid was about ready to walk down here and die and Glenn saved his life by getting the boulder out of the way," the cameraman is heard saying. "So it's all about saving lives here at Goblin Valley."
After the rock falls, the three men laugh, cheer and high five each other.
Utah State Parks officials Thursday were not so amused.
"It is not only wrong, but there will be consequences," said spokesman Eugene Swalberg, noting that a criminal investigation is underway by State Parks authorities.
"This is highly, highly inappropriate," he said. "This is not what you do at state parks. It's disturbing and upsetting."
Swalberg said it's rare for tourists to destroy natural formations.
Geologists say the rock dates back about 165 million years though the toppled formation was formed no more than 20 million years ago.
Deputy Emery County Attorney Brent Langston said he was aware of the incident, but it hasn't been presented to his office yet for screening for possible charges.
"It's not one we see every day," Langston said.
"Some things can't be replaced, like photographs in a family album, but they have great sentimental value," he said.
He said anyone involved, including anyone who encouraged the criminal behavior, could face anywhere from a class B misdemeanor to a second-degree felony depending on how much the formation is valued.
Glenn Taylor said Thursday afternoon that he was the man who pushed over the formation, while Dave Hall filmed and Dylan Taylor looked on. According to Taylor, he and Hall are leaders for a local troop of the Boy Scouts of America. Hall added that the men also were acting as Church of Jesus Christ of Latter-day Saints youth leaders.
Taylor said he knocked the boulder to the ground after seeing a family walk by on a nearby popular path. When he touched the rock, Taylor noticed it was loose.
"I put my hand on a rock and it moved," he said. "While we were sitting right there we thought, 'Man if this rock falls it'll kill them.' I didn't have to push hard."
Taylor said that at the time he thought he was doing a "civic service" by taking down a loose rock. However, as he walked back to his car, he began thinking that he should have contacted a ranger about the loose rock. He also said he wished he could take back his actions.
"Glad we did it, wish we wouldn't have done it," he said Thursday of his feelings about the incident.
Hall agreed with Taylor and added that the park was especially crowded that day, Oct. 11, due to national park closures during the government shutdown. The men were worried that a child would be crushed by the boulder, he said, and during his time in the park he only saw one ranger, who was stationed at the entrance.
"With the information we had we made the best decision we could," he said. "We weren't there for vandalism or anything like that."
Hall also said that Taylor recently underwent shoulder surgery and has little upper body strength. The fact that Taylor could still push the formation over demonstrates how loose it was, Hall said.
"The intent was to enjoy the natural resources with a bunch of friends," he added. "We're extremely sorry for our actions. There was no in way shape or form any intent to go out there and cause any harm to our natural resources."
The Facebook video received a barrage of praise from the men's friends.
"Too funny," wrote one person.
"You have so much fun!! Thanks for saving a life [smiley face]. Rock On," wrote a second.
The rock pusher, Taylor, wrote that they were "just doing our civic duty!"
When a person warned that the men should remove the video before they go to jail, Hall fired back.
"Nobody's going to jail," he wrote. You have a 2,000 lb boulder that is teetering on a 2"[sic] dirt ledge and about ready to fall off on it's [sic] own. 5 minutes before this video we watched a family with many small children walk right below the rock to take a family photo. We didn't do anything until they were gone because we didn't want anyone to get hurt. One gust of wind and that rock was falling whether someone was there or not. ...
"I'll take my chances with the cops rather then my conscience after hearing a family was crushed to death by a rock I was prompted to move."
Swalberg said just because a rock looks loose, it doesn't mean people should knock it over.
Yes, it and other rock formations in southern Utah will fall one day, likely generations from now, but "that doesn't mean we go and push over Delicate Arch because we're afraid it's going to topple," he said.
Swalberg said the priceless goblin formation won't be able to be restored.
According to Taylor, he has not been contacted by any authorities about the incident.
He added that since news broke of the video, reactions have been negative and he was "accosted" by a television camera crew Thursday. Still, he said the issue goes back to his decision to push over the rock, not with the video that ended up online.
"The issue is we did it," he said. "I wish we wouldn't have."