What would you do if you heard a noise in the night and discovered a stranger in the house? Offer him a midnight snack? A hoodie, if it’s chilly? A ride home? That’s how some residents react to a home invasion in the student-saturated neighborhoods surrounding Penn State University. True, some of them grab baseball bats and call the police, but once they realize the intruder is an inebriated undergraduate who has no idea where he is, the adrenaline rush ebbs and empathy kicks in.

“I was a college kid,” reasoned David McClelland, a homeowner who confronted an uninvited guest. “I remember doing some dumb stuff.”

“The mother in me came out,” is how Meredith Doran put it. A stranger came banging on her back door one frigid winter morning. Seeing his thin hoodie, she let him in, offered him crackers and water and then a ride home. “His vibe,” she explained, “was not a menacing one.”

The same cannot be said of Ms. Doran’s husband, Matt Jordan, who, a couple of years earlier, had grabbed a bat to confront a student in boxer shorts and knee-high black socks who sat on their sofa with his head in his hands.

“Who the hell are you?” asked Mr. Jordan, who is as physically imposing as an N.F.L. tight end.

“I’m J.T.,” his visitor announced, as if his identity should have been obvious.

“J.T.,” Mr. Jordan recounted, “if you don’t get out of the house now, I’m going to call the police. And he said, ‘Dude, really?’ And I said, ‘Yes, really.’”

The townies have a name for these intruders: Red Bull Zombies. Before hyper-caffeinated beverages like Red Bull, students could consume only so much alcohol before passing out. Now, they’re no less addled but the stimulants keep them ambulatory, and so they blunder into the wrong houses.

There are as many students as there are full-time residents in the State College area. Most locals tuck themselves away in quiet suburban enclaves. Those who dwell among the students so value their neighborhood’s historic houses, tree-lined streets and proximity to downtown and campus that they’re willing to put up with what they call the “dumb stuff.” And some positively enjoy the antic energy of their young neighbors.

“There’s a pulse to the neighborhood,” said Joel Weidner, who called the police when he heard someone “thudding around” in his basement a few years back. A drunken student had crashed through a basement window. “Suburbia would be boring.”

While these victims of home invasions see the humor in their experiences, they’re keenly aware that their community, like so many college towns, has a serious drinking problem. Just this year, after a night of alcohol-drenched hazing rituals, a fraternity pledge fell down a flight of stairs and later died. In response, the university has increased its oversight of the Greek system. Among new restrictions, it is reducing the number of fraternity parties with alcohol that it issues permits for, from 45 a semester to 10 (wine and beer only, and no kegs).

It’s hard to know how often the Red Bull Zombies strike, because many trespasses go unreported and the ones that are called in are variously classified as criminal mischief, public drunkenness, underage drinking or disorderly conduct. The State College police chief, John Gardner, guesses that 5 to 10 student invasions occur a year. There’s potential for harm, of course, for residents who let their guard down as well as for invaders. In 2014 in Sterling, Va., an inebriated teenager was shot and killed when he stumbled into a neighbor’s house.

Sometimes the residents haven’t locked up; sometimes the uninvited guest breaks through a window or flimsy door. In most cases, “it’s not an attempt to commit a crime,” Chief Gardner said. “They truly believe that’s where they live.” Or where their friends live.

Consider the head-spinning dialogue when Barbara Nilson found an intruder on her couch, removing his shoes.

She: “Why are you in my house?”

He: “Because you said come in.”

She: “I did not say come in, and you need to leave.”

He: “Well, why would I be here if you didn’t say come in?”

She: “Because you’re very drunk and confused and you need to leave.”

Finally, he put his shoes on and left.

Jackie Sobel, who has lived among students for close to 50 years, called the police about a would-be intruder one snowy night: He wouldn’t stop banging on the door even after she told him he was at the wrong house. But when she saw that the guy was bare-chested, she brought him a T-shirt.

“I couldn’t stand to see him in the cold,” she said.

Her neighbor Nina White, another half-century resident, also took pity on an unwelcome visitor. Hers is the most famous story in the neighborhood, perhaps because it most resembles the trespass of Goldilocks into the home of the Three Bears. She was making dinner when her daughter tugged at her elbow.

“Mommy, Mommy,” the child said, “would you get that man out of my bed? I want to play in my room.”

Ms. White thought her daughter was being silly. “There’s no man in your bed,” she said. But the girl insisted — three times, as in the fairy tale — so her mother checked, to humor her. Sure enough, a student was zonked out in her room.

Ms. White didn’t scream. She didn’t call the police. Instead, noting that, drunk as he was, her intruder seemed to have taken care to let his shoes dangle off the end of the bed, she pronounced him “some mother’s son.”

When she woke up the mother’s son and asked him if he knew where he was, he looked around at the posters of animals on the bedroom walls and said, “I’m in some enchanted land.”

Ms. White lent the disenchanted youth a coat and escorted him to the fraternity house he had been aiming for in the first place.

Arguments about whether an intrusion is actually taking place — and if so, who is the intruder and who is the intruded upon — are common.

The first thing David McClelland’s couch surfer said when roused was, “What are you doing in my room?”

When Mr. McClelland tried to explain that he had it backward, his visitor challenged him to a fight — just as soon as he returned from the bathroom. Mr. McClelland was happy to show him the way. He opened the front door and the student, clad only in boxer shorts, stepped outside — and urinated on the front porch. The police officer summoned by Mr. McClelland waited until the young man was finished, then cuffed him and hauled him to jail, dressed as he was.

So that was the end of that. Except Mr. McClelland found that the student had also relieved himself on the couch.

When they met in court a few months later, and he realized the boy was a freshman in his first semester, his desire to punish evaporated.

“Yes, somebody peed in the house,” he said, “but nobody got hurt, nobody was injured, nothing was stolen.” And when the student reimbursed him for the damage to his sofa, “we got a nicer couch out of the deal.”

Jackie Sobel obtained a different sort of satisfaction when she met her intruder in court. “I said I didn’t want to take it any further,” she recalled. “I just wanted to scare him as much as he scared me.”