(GIF via YouTube)

Legend has it that an ape-like creature lurks in Mount Everest’s foothills, feasting on sheep and yak. Some claim to have seen it — a critter with four legs and massive body hair that sometimes leaves a trail in the snow.

Cue the Abominable Snowman, or Yeti.

Though the animal’s existence has never been proven, that has not stopped many from searching. Over the decades, climbers — including the first to make it to Everest’s summit, Sir Edmund Hillary — have reported curious footprints or suspicious sightings on the way to the top.

[Bigfoot: still imaginary, probably not an undiscovered species of bear]

The National Archives recently posted a 1959 U.S. government memo issued from the American Embassy in Kathmandu: “Regulations Governing Mountain Climbing Expeditions in Nepal — Relating to Yeti.” It outlined guidelines for a Yeti expedition, including what to do during a monster encounter. Here are the highlights:

1. A permit fee must be obtained prior to a Yeti expedition. It cost $5,000 rupee, or nearly $77, and must be paid to the Nepal Government.

2. Hunters can photograph or catch a Yeti but not shoot or kill it — unless in self-defense.

“All photographs taken of the animal, the creature itself if captured alive or dead, must be surrendered to the Government of Nepal at the earliest time,” the memo stated.

3. Any evidence showing that the Yeti is real must be immediately turned over to Nepal.

“News and reports throwing light on the actual existence of the creature must be submitted to the Government of Nepal as soon as they are available,” it stated, “and must not in any way be given out to the press or reporters for publicity without the permission of the Government of Nepal.”

(The National Archives)

Mark Murphy, an archivist with the National Archives, said he ran across a copy of the memo several years ago in records from the U.S. Agency for International Development.

“Your eyes get sort of drawn to it because of the subject matter,” he told The Washington Post.

Murphy said it has been reported that the guidelines were first written by the Nepalese government and then copied by the U.S. government. He warned, however, that the document does not prove that the U.S. government believes in Yeti.

“It’s just an administrative document telling you what to do if you want to look for it,” he said. “But it’s still pretty cool. You don’t expect to come across something like that.”