Jazz Tangcay Artisans Editor SPOILER ALERT: This story discusses major plot points, including the ending and the post-credits scenes, for “Ant-Man and the Wasp: Quantumania,” currently playing in theaters. While improvising in a meticulously crafted Marvel movie — full of CGI, green screens and elaborate costumes — seems nearly impossible, Paul Rudd and Jonathan Majors did just that “Ant-Man and the Wasp: Quantumania.” According to editors Adam Gerstel and Laura Jennings, Rudd, who plays Scott Lang/Ant-Man, and Majors, who plays the MCU’s new Thanos-sized villain Kang the Conquerer, especially exercised their improv muscles during two similar scenes — one which features a multiplied Ant-Man and another, an army of Kangs.