Emma Seligman’s “Shiva Baby,” her feature debut, was originally slated to premiere at SXSW last March. A few days before its world premiere, the COVID-19 virus was declared a pandemic, and every event in the country, including SXSW, was forced to be canceled. I saw Seligman’s film around that time and was floored by the swirling energy of her camera and the edge-of-the-seat mise en scène. Seligman, who wrote, directed, and co-produced the film, manages to turn a Jewish day of mourning into a frightfully comic treat.