"In the late 1800s, fishermen and boaters started reporting something other than rock pyramids in the lake. They had seen a giant, snake-like creature in the lake. Most lake monsters are usually said to be curious and shy, but this one was not. Fred Seaver, a fisherman, said it took his line and pulled him across the lake for a mile-and-a-half. Another fisherman said he actually speared it, but it was too strong for him to drag to shore. The people around the lake dubbed it 'The Terror.'
"As the years passed, the creature seemed to grow more aggressive. Two men racing in rowboats said they saw a monster with an upraised head and jaws lined with teeth. The men tried to fight off the monster with their oars, and were soon joined by some men who had rowed out with a shotgun. By the time the others got there, the creature had disappeared under the water and left a foul stench behind.
"Sightings stopped in Rock Lake as time went on, but then started in Red Cedar Lake, located about 5 miles away. Some people think 'ol Rocky left Rock Lake and went to Red Cedar Lake. After awhile, reports also stopped coming from Red Cedar Lake. Some think the monster worked his way back to Rock Lake, and he was seen there in 1943. Joseph Davis saw about 6 feet of the monster rise out of the water.
"Rocky has not been seen much since then."
This post is excerpted from my book Cryptid U.S.: Tales of Bigfoot, Lake Monsters, and More from Across America, which covers Rocky and various other lake monsters.