|Habitat||Columbia River, Oregon|
Colossal Claude, also known as Marvin the Monster, is the name given to a sea monster spotted near the Columbia River in Oregon.
Colossal Claude is said to be 15 to 40 feet long, with an 8 foot long neck. It has a round tan body with a snake, horse or camel-like head and a long serpentine tail. 
Colossal Claude was first reported in 1934 by L.A. Larson, first mate of the Columbia River Lightship. He described what he saw as a 40 foot animal with a "neck some eight feet long, a big round body, a mean-looking tail, and an evil, snaky look to its head." Other crew members on the Lightship watched the creature with binoculars. 
Colossal Claude was seen again in 1937 by the crew of fishing trawler Viv. Charles E. Graham, captain of the Viv, described it as a "long, hairy, tan-colored creature, with the head of an overgrown horse, about 40 feet long, with a four-foot waist." Few months later, a couple sighted a creature they described as looking like an "aquatic giraffe" along Devil's Churn. 
In 1939, crew of halibut fishing ship Argo also saw Colossal Claude. It reared up over the water ten feet away from the hull of the ship. The crew watched it eat fish before they turned away from the creature. It was described as having a camel-like head with coarse gray fur. It had glossy eyes and a bent snout.
In 1963, the Shell Oil Company during an oil search off the Oregon coast recorded a video tape that shows a 15 foot animal with barnacles ridged along its body. It swam in a corkscrew fashion in 180 feet deep water. This recording gave Colossal Claude the nickname "Marvin the Monster."
- Eberrhart, George M. (2002) Mysterious Creatures: A Guide to Cryptozoology ABC-CLIO, Inc. ISBN 1-57607-283-5
- Offbeat Oregon: "Colossal Claude," the great Columbia River Bar Sea Serpent
- Columbia River's Colossal Claude
- Tales of Claude and Marvin