Gunnar Boettcher, a 20-year-old student at Gustavus Adolphus College in St. Peter, and his brother took photos and video of the rabbit, which looks to have tumors growing on its head, on June 26.
"We've seen it before around the house but we've never been able to get a close look," Mr Boettcher said. "But we went over to him that day and he didn't run away like he normally does."
In the video, entitled The World's Scariest Rabbit, Mr Boettcher speaks in an Australian accent, imitating the late crocodile hunter Steve Irwin.
Mr Boettcher put the video on Facebook, and a friend of his posted it to Reddit. Within four days, more than 200,000 people had watched, according to The Free Press of Mankato.
Mr Boettcher last saw the rabbit on Wednesday night. He thinks it might have a papilloma virus that's a form of cancer.
Joe Stangel, area wildlife supervisor for the state Department Natural Resources, said he also suspects that is what it is but is waiting for confirmation from a veterinarian. It's not an uncommon ailment in rabbits, Mr Stangel said, but he's not seen it on the top of the head.
It's generally a fatal ailment, Mr Stangel said, noting the DNR would just let nature take its course.
Some of the video comments haven't been particularly kind to Mr Boettcher. Some say it's wrong to get a few laughs from a disease that certainly will kill the animal. Others say he has a responsibility to get it some veterinary help.
Mr Boettcher disagrees.
"It's a great idea to try to help him and make him healthy again, but it's a little ridiculous to blame me for not helping the rabbit and taking him to the vet when it's a wild rabbit," he said.
"It's turning into a thing on animal rights ... it was just supposed to be something fun between me and my brother."