- sea slug
- very low tide ... exposed tide pools
The owner of Elkhorn Slough Safaris holds a very large sea hare stranded on a muddy bank of the slough.
Sea hares used in medical research: https://cc1.rsmas.miami.edu/slugs/scientific-importance.html
"The purple ink of one species of sea hare was used by ancient scholars in Jerusalem to write sacred texts-- maybe even the Old Testament!" www.squidoo.com/sea-hare
The purple ink of molluscs has been used to create a clothing dyes: http://en.wikipedia.org/wiki/Tyrian_purple
Unsure of official name help? Found in second intertidal zone