NEW YORK — Last night Tavi Gevinson, the world’s most trusted 15-year-old fashion blogger/editor-in-chief, proved her talents aren’t limited to all that. “I’m a seasoned theater kid,” she told us at the Standard Hotel East Village, where at midnight she screened “Cadaver,” a new eight-minute animated short written and directed by Jonah D. Ansell, in which she acts and sings. The movie is the half adorable, half macabre story of a medical student (Gevinson) in a morgue forced to help the dead body of an old man (Christopher Lloyd), recently brought back to life, reunite with the wife (Kathy Bates) who survived him. The undead geriatric, carrying his own heart in a jar, makes the med student drive him home, making frequent pit stops to pee and buy beef jerky on the way. It's a delightful ride, and Bates and Lloyd have both agreed to star in a feature-length version if one is made — although the current ending should please both romantics and anti-Valentine's Day types alike.

“It’s definitely melancholy, like all of my favorite things,” Gevinson, sporting all black save her red-accented saddle shoes, said. “It’s very hard to do a love story that isn’t cliché, so this one is a little more bittersweet.” As for the party, the highlight — beyond the Abramovic-esque labcoat-wearing bartenders popping popcorn, spinning pink cotton candy, and passing around those too-tiny Cupcakes by Melissa (giving this party the Fashion Week’s highest calorie count) — had to be Gevinson taking the mic to sing Neil Young’s “Heart of Gold.” (Young himself granted Tavi the rare privilege of recording his music, which appears in the film.)

After the screening, guests cavorted with the various skeletons and mad scientists brewing pink cocktails in beakers, and on the way out were rewarded with heart-shaped red-velvet whoopie pies in mason jars. It was almost too much. Gevinson was on the dancefloor with fellow indie-lets of the black-framed-glasses-and-vintage-dress variety. What was in the 15-year-old's glass? A shirley temple, she told us. Sweetness quotient met.