UCSC's mascot is the banana slug (specifically, Ariolimax dolichophallus). In 1970, volleyball team member David Van Cleve created the mascot "Banana Slugs" for the UCSC volleyball team. He was concerned that, as sports began to gain in popularity at the institution, a team name or mascot did not exist. His roommate, Bob Grindeslug (no relation), silk-screened uniform shirts for the entire volleyball team in preparation for the All-Cal tournament that year. After their graduation in 1972, the team name was no longer used until 1974, when the UCSC club soccer team reinvigorated the Banana Slug mascot. Three soccer team members, Larry DeGhetaldi, Fred Bicknell, Sven Steinmo and their roommate, Richard Hedges, chose to name the team the Banana Slugs before an All-Cal tournament. The team's unusual name was noted by the San Jose Mercury News after the team suffered a humiliating defeat against the San Jose State Spartans.
In the Fall of 1972, when the club basketball team became formalized (with a coach and expanded schedule), the athletic director at the time, Terry Warner, informed the team that they needed to have a mascot and that it had been chosen to be the Sea Lions. The team summarily rejected that name, claiming to not need any mascot. Consequently, their uniforms simply said "UCSC" on them and there was no recognized mascot. In 1980, when the university began more formally participating in NCAA intercollegiate sports, the then-chancellor and some student athletes declared the mascot to be the sea lions. Most students disliked the new mascot and offered an alternative mascot, the banana slug. In 1986, students voted via referendum to declare the banana slug the official mascot of UCSC – a vote the chancellor refused to honor, arguing that only athletes should choose the mascot. When a poll of athletes showed that they, too, wanted to be Slugs, the chancellor relented.
A chemistry major UC Berkeley transfer student to UCSC asked student activities for some service projects for Porter College. She was made the first Porter College mural committee chairperson and was asked to represent Porter College to the Mascot Committee at the time. She had a good background in student government and had some experience as an amateur Parliamentarian. A few mascot meetings were held, perhaps without quorum, and the Porter College representative was lobbied by the athletes and the science professors.
On the way to the important (final) Mascot Committee meeting, she stepped on an extremely flatulent banana slug, and so it was decided in that moment to push for the Banana Slug. Knowing quorum was important, with one member allowed from each College, on the way to the meeting she found a Kresge student to be the Kresge representative. The leader of the committee was against the idea of the Banana Slug and taken aback to see the Porter College representative suddenly appearing to take control. He tried to say no quorum, so no decision, but a count was forced, and quorum was established. The Porter College representative had already gotten the Kresge representative to go along and second any motions she was going to make. She moved to make the Banana Slug the mascot, and was seconded immediately. The committee leader protested. Then, she quickly motioned to ratify by referendum (moved to a vote by the student body), and was immediately seconded, so moved. She then essentially organized and ran the vote, as she had been trained to do in her earlier days participating in student government. She knew that students would need their student body card to vote and so she rallied several classes to bring their cards and to vote.
The day of the vote, she rallied for students to go to the voting table. It was a surprise to administration that so many students showed up with their student body cards and voted. There were some irritated faculty (including the chancellor) that made their opinions known as the voting was being set up, so the Porter College representative decided to stay anonymous when she was called to do the People Magazine interview. She was told by the chancellor that the election didn't matter and the sea lion would be the mascot. Eventually, the sea lion statue was removed from where it had been placed.
The June 16, 1986, issue of People magazine featured a full-page spread dedicated to the selection of the Banana Slug as the official mascot of UCSC. In February 2008, ESPN Sports Travel named the UCSC Banana Slugs as one of the ten best nicknames in college basketball.
The "Fiat Slug" logo prominently featured on campus is a trademark of UCSC owned by the Regents. It was developed by Bernt Wahl and two other students during the mascot controversy, who later incorporated as "Oxford West" and licensed their design from the Regents to produce clothing inspired by the university. The slug also is featured along with the school's logo on Vincent Vega's T-shirt in the 1994 film Pulp Fiction.
A sea lion statue can still be seen in front of the Thimann Hall lecture building.