“Oh my god. Four years I’ve waited for this. Four years.”

The speaker, dressed as a tennis player and lost somewhere in the human mass that is Del Playa on Halloween, was positively giddy. Jumping up and down and repeatedly invoking the almighty, the senior UCSB student stuck out his hand and introduced himself to Chancellor Henry T. Yang. Breathlessly, he told the chancellor that he’d been looking for him every Halloween since freshman year.

After a few photographs, Yang and his wife Dilling moved on and continued their annual stroll down DP. A few seconds later, the crowd the couple left behind burst into a cacophony of excited screams and tribal dancing.

“They’re just looking for any excitement,” Chancellor Yang said with a smile, trying to play down the incident.

Yang has been walking Isla Vista on Halloween since he became chancellor in 1994, and despite the modesty, he was greeted like a rock star on Friday’s tour of DP. Walking arm in arm with Dilling, the chancellor spent the better part of two hours this weekend surveying the party that I.V. has become famous for.

The night began at about 11 p.m. at the police barricade on El Embarcadero Road. Yang spent a few minutes chatting with police officers he recognized from years past about the crowds and glad-handing with local politicians before he pushed ahead into the sea of people that police estimate was 45,000 deep.

The first item on the night’s agenda was an ocean-side party. Yang teaches a class every year, and at Friday’s lecture he had asked if any students were having parties. He had a list of bashes to crash, and the first was smack dab in the middle of the 6500 block.

As the chancellor made his way toward the party, the balcony above hushed, and someone yelled, “Holy shit, it’s the chancellor.” When he walked in the door, the houseful of students exploded into a series of “Olés” and “Chancellor, Chancellor.” Mobbed, Yang shook hands over the beer pong table and spent a few minutes on the balcony talking to students.

A few minutes later, after he had made his escape, Yang marveled at the scene.

“I did not know that there could be that many people [at a party],” he said.

With Dilling in tow, Yang soldiered on down DP, commenting on costumes and stopping for anyone who approached him. As he squeezed through, Yang talked about Halloweens past, and the invasion of out-of-towners that has become the norm in recent years.

The hordes of visitors that make up the majority of the revelry are a problem, Yang said, and he worries for students’ safety.

“It would be nice if there weren’t that many out-of-towners,” he said quietly.

Yang had no doubts about the makeup of the crowd – “Mostly these are not our students – if they were, they would be able to say ‘hi’ to me,” he said – and as the night progressed it became clear that the chancellor is a virtual proof of residency test. All throughout the crowd, students – vastly outnumbered on DP – spotted Yang and darted to catch his attention as out-of-towners passed by with blank faces.

There’s an anatomy to a Chancellor Yang spotting on Halloween. Most begin with a shocked face and a double or triple take as the partier passes by. Often times this is followed by a high-pitched shriek of “Chancellor Yang.” Next, most students’ posture improves dramatically and their language is formalized. After a short conversation, (“I’m honored to meet you,”) and a few pictures (“for my mom,”) the student and the chancellor both part ways, smiling.

Yang relished in meeting students and shrugged off the semi-violent throngs of out-of-towners who did not recognize him.

“They thought someone brought their parents into town,” he said about his encounters with visiting partiers.

As Yang and his wife advanced down DP, the chancellor spotted numerous students in his mechanical engineering class and raced to flag each down. One, a tall man in a short skirt, told Dilling that the chancellor’s course was his favorite.

As they walked away, Yang boasted about the class he had held that day, on the Friday of Halloween.

“Today,” he said, “I had 90 percent attendance.”

The first couple of UCSB capped off their tour of Del Playa at another student’s party on the 6700 block. It was pushing 1 a.m. as the chancellor approached, and the revelers were in the front yard, watching the makeshift parade down DP.

“Chancellor Yang, you made it,” the student yelled. Then, quieter and almost as an aside, “he fucking made it.”

At the party Yang politely declined a shot and asked about costumes. Noting the time, Yang excused himself and the chancellor and Dilling made their way down Sabado Tarde, back to campus.

Off I.V.’s main drag, Yang was confronted by a few uncomfortable images. The first, a partier passed out on top of two cars, elicited groans. The second, a dangerously drunk couple fighting with consciousness on a car’s hood, seemed to distress Yang.

At the home stretch, on Trigo Road in front of the makeshift emergency care tent next to the Isla Vista Foot Patrol substation, Yang lingered and looked at the seriously injured.

“I feel so sorry for them,” Yang said before he made his way back to campus.