The Whamola is an electric, upright bass-like instrument, somewhat akin to a washtub or gastank bass. Its name, and indeed its construction, are a portmanteau of "Whammy bar" and "viola".
Popularized by Les Claypool, of Primus fame, the Whamola is still a relatively obscure instrument. They are available for purchase on a semi-custom basis from various manufacturers, primarily in the United States, as listed in footnotes. Most Whamolas, however, are hand-build by individual musicians. As such, variations are the rule, rather than the exception.
The Whamola is held in the manner of an upright bass, and generally come in two sizes, 42" or "full sized" or the smaller 34", sometimes called a "fun size". Les Claypool's "Steve Whamola" is a full size, and is the most often emulated.
Rather than being played with a bow, as with a classical upright bass, or with a plucking or hammering motion of the fingers, the string is struck or otherwise manipulated with a drumstick. In addition to fretting the string with the supporting hand, a handle similar to a whammy bar, which is sometimes connected to a more complicated pulley system, is used to directly adjust the tension of the string to alter the sound.
Typically, the electronic components for a Whamola, such as jacks and pickups, will be salvaged from a standard electric bass, with the rest of the instrument being fabricated from new or salvaged materials as diverse as cast-off wall studs and aircraft grade aluminum. Traditional materials such as ebony and mahogany with brass hardware are popular choices for professionally crafted Whamolas.
Whamolagans, Ojai CA
Whamola Laboratories, Portland OR
Keven Barnett's Whamola Project
Gear of the Godz - How to Build a Whamola