In the bathroom of an apartment on the Lower East Side of Manhattan, on the first night of spring, Philip Santos Schaffer, who is twenty-seven, sat cross-legged in a dry bathtub, looking like the Buddha’s brother from Brooklyn. He was wearing shorts in a blue Hawaiian print and a matching shirt, under a Michael Kors women’s blazer from a thrift shop; his black hair was in a bun. “The world is about to end, and this is the only place to survive,” he explained, in an agitated but not crazy way, to Michelle Stern, who owns the apartment, and her friend Thomas, who lives nearby. Stern and Thomas sat on two wooden chairs sardined into the space next to the tub and in front of the toilet. Turning on the tub’s faucet, Santos Schaffer held up a mug and offered his companions coffee, tea, or ramen “made with N.Y.C.’s finest tap.”

Here’s the great news: there was room for one more person in the tub, Santos Schaffer informed Stern and Thomas. Both declined the chance at salvation.

Santos Schaffer is an actor, and Stern and Thomas were the audience. Santos Schaffer was putting on an original play for them, “The End of the World Bar and Bathtub,” an interactive piece that takes place in your bathroom, providing you have a tub. (Tickets are a hundred dollars for two, which is the most and least you can purchase.) He débuted his play in March, 2018, and is approaching his fiftieth performance; if records of this sort of thing were kept, Santos Schaffer might qualify as the longest-running Chicken Little Off Off Off Broadway.

“I love the idea of making something that tours to people and can be as immediate as watching a video on YouTube,” Santos Schaffer said after the hour-long show. “So far, I have plays for living rooms, closets, and bathrooms, and, ultimately, I want to write a play for every room of a house.” The script for the bathtub play is nineteen pages, but Santos Schaffer uses it as scaffolding on which to improvise. “I try to listen to what type of experience the audience wants to have,” he said. “Some nights, people really want to talk. Some people want to laugh. Some people want to be scared.” A week earlier, he’d performed at 9 a.m. for a couple who’d flown in from San Francisco the night before and requested that he come to their tiny room at the Standard Hotel. Another theatregoer had booked the play as a surprise for her partner, who turned out to be un-delighted by it.

Before each performance, Audrey Frischman, the play’s director, gives a curtain speech in which she advises the audience to use the rest room before it turns into the theatre.

Santos Schaffer and Frischman formed their first theatre company during their senior year at an arts-oriented public high school in Los Angeles. Santos Schaffer later received a B.F.A. in directing from Hofstra and an M.F.A. in dramaturgy from Columbia. In 2014, the pair founded WalkUpArts. “All of the plays are built around pushing audiences to experience empathy in a new way,” Santos Schaffer said. “And all of them are solo performances in which audience interaction is slowly scaled up until, by the end, the audience is asked to make a big action or choice, such as whether or not to survive the end of the world.”

In addition to the bathtub play, WalkUpArts’s upcoming projects include Santos Schaffer’s “Baby Jessica’s Well-Made Play” and a revival of his “A Play About Drew Carey.” In the latter, a fictionalized version of Drew Carey believes that, if everyone in the world could laugh together at the same joke, killing would cease. The Baby Jessica piece was inspired by the little girl who fell down a well in Midland, Texas, in 1987. In the first act, one audience member privately listens to an audio track. In the second act, that same person sits in a closet while an actor talks to her over a baby monitor. There are two more acts, but let’s keep a few plot twists untold.

As the play wound down, Santos Schaffer grabbed a notebook and a pencil. “Before you go, if there’s anything you could leave me with,” he said, “something to ponder when I’m running out of thoughts, or something to laugh about, I would appreciate that.”

After some consideration, Thomas said, “I would make a list of all the things that could kill me even if I stay in the bathtub, and then put the list on my wall.”

Santos Schaffer scribbled.

Stern asked him, “Do you have a phone in here?” He did not. “Then, maybe write your mother a letter while you wait before the world ends.” ♦