The Lake Merritt Monster here (aka Oak-ness Monster) is your typical Loch-Ness-style monster that's supposed to live in Lake Merritt.
"Recorded Lake Merritt monster sightings date back to the 1940’s. According to Jack Burroughs, a former reporter for the Oakland Tribune, the monster once inhabited the lake and then left (although, if Dr. Bailey is correct, he seems to have returned again). On June 21, 1946, Burroughs wrote in his weekly column:
The legend, which some go so far as to disbelieve, dates back to that far-off time when turgid streams snaked their way down from the hills to form the San Antonio creek. On a day of untoward lightnings and unseemly thunderings a vast, slimy, amphibious creature slithered along one of these water courses into San Antonio creek, waded along the creek till he came to the estuary, swam out the estuary into the Bay and thence out to sea. But before he left he hollowed out with a fillip of his tail, the basin that later became Lake Merritt. He must have been wired for sounds, for before he left he roared, in a voice that echoed from Mt. Diablo to the Farralons, a prophecy that has since been freely translated from the old Crow Indian dialect as follows: “Lake Merritt… home!”
This archival article was recently dug up from Oakland’s Main Library by Oakland resident and artist Justin Kanalakis, who has quickly become a monster buff and started making and selling t-shirts with the creature’s likeness."
A July 2, 1948 Oakland Tribune column by Burroughs continues:
Has the Lake Merritt sea serpent returned? Has the legendary Indian prophecy concerning the monster of San Antonio Creek finally been fulfilled? Has the ... But let's leave off asking questions and answer a few...I was struck by the fact that the picture bore a remarkable resemblance to "Fafner" (Fáfnir) the Wagnerian dragon brought over from San Francisco's War Memorial Opera House in 1946 to impersonate the legendary Loch Merritt monster in a learn-to-swim campaign. 1
This refers to his June 21, 1946 column when "Fafner" came for a visit. 2
Learn more about Oakland urban legends.