In the early 1900s, the region also earned the nickname of "Devil's Country", after several prospectors claimed to have encountered or witnessed "devil-creatures"—alleged to be a form of bipedal, ape-like humanoid, such as sasquatch (i.e. "Bigfoot").

In 1900, the first documented account of the alleged "devil creatures" of Thomas Bay was written by Harry D. Colp, who had had been staying in Wrangell with three of his fellow prospectors, identified only as "Charlie", "John" and "Fred".

At some point in the springtime of 1900, Charlie received a tip-off from a Thomas Bay native on how and where to find gold there: "He told me to go up to Thomas Bay* and camp on Patterson River on the right side, travel upriver for about 8 miles (13 km), and then turn to the high mountains, and after traveling about a mile and a half, I would find a lake shaped like a half-moon."

Upon setting the quartz down in the men's shared cabin, Charlie is said to have requested a meal be made for him, so he may eat and retire to bed promptly.

When he finally returned, he stated to the others that a ship was departing the following morning, bound for Seattle, which he wanted to join as a passenger, as he desired to "never see Alaska" or hear the words "Thomas Bay" ever again.

Charlie then recommended to the other men to never go prospecting in Thomas Bay themselves, as it would only cause unwanted "mental and physical pain", and that if they could collectively pitch-in enough money for his ticket to Seattle, he would recount exactly what had happened to him on his trip.

Charlie said it began raining heavily for several days, causing him to remain stuck at his campsite, where he resorted to eating and sleeping much of the time.

In 1925, a trapper reported losing a dog in the hills around Thomas Bay, but finding strange tracks, with the hind feet resembling a cross between a bear's and a human's footprints.

She did say that large amounts of arsenic were alleged to be present in the watershed at Thomas Bay, which may or may not serve to explain the strange events reported by visitors.