The most obscene mollusk you will ever encounter. Common to Puget Sound (and similar areas west) this clam has a seven inch phallus-like neck similar to an uncircumcised penis.

Both interesting and revolting.

Images of the geoduck can be found at the following URLs (hopefully at least one will still be working should this be read in the future):

http://www.ecy.wa.gov/programs/sea/pugetsound/species/geoduck.html
http://www.pac.dfo-mpo.gc.ca/ops/fm/shellfish/Geoduck/biology_geoduck.htm
http://www.sportfishing.bc.ca/Fish/geoduck.cfm (by far the most disturbing)
http://www.geoduck.org/Go_files/GO_ABOUT.html

Properly pronounced, the first syllable sounds like GUI.

The first link in the list also contains the enjoyable quote

Whenever I visit the seacoast, I derive pleasure just knowing that several feet beneath my waterproof boots lies an animal quite possibly 90 years my senior, silently finishing a supper of diatoms and algae inhaled through its meter long neck.
      - David George Gordon, Field Guide to the Geoduck

The geoduck is the mascot for the Evergreen State College -- up there with the UCSC Fighting Banana Slugs for the best mascots I know of. Every year at graduation the graduating greeners can be heard to sing the following ditty:

Go Geoducks go
Through the mud and the sand
let's go
Siphon high, squirt it out,
swivel all about,
let it all hang out.

Go Geoducks go
Stretch your necks
When the tide is low
Siphon high, squirt it out,
swivel all about,
let it all hang out.

Ge"o*duck (?), n. [American Indian name.] Zool.

A gigantic clam (Glycimeris generosa) of the Pacific coast of North America, highly valued as an article of food.

 

© Webster 1913.