When the pictures first surfaced some in Montana doubted they could even be real.
But now the photographer has surfaced and he's talking to KTVQ-TV. Alex Wypyszinski took the pictures last April after dropping his wife off for work:
"I thought it was a horse and carriage," said Wypyszinski. "That was the kind of noise that I heard."
By the time he turned around, the two fuzzy brown images were racing quickly toward him.
Wypyszinski pulled out his camera quickly, thinking he was going to catch two moose racing down the highway.
He quickly learned he was mistaken.
"I thought I was having a hallucination or something," said Wypyszinski. "I couldn't believe what that buffalo looked like."
It was a bison, badly burned from an encounter with one of the numerous hot spots in Yellowstone National Park.
The sight of such an injured bison alone is rare, but what Wypyszinski saw next was once in a lifetime.
"Never, ever, ever," said Wypyszinski. "I've seen plenty of bear, and more buffalo. But I've never seen anything like that before."
Here's part of an audio interview with Wypyszinski:
See all 14 of the pictures here.