In "Sock Opera," Mabel offers some to Dipper, who'd been up all night trying to unlock the laptop found at the bunker. Later in the episode Mabel says she drank "four mega-shots" of it, and this is the reason she has a lot of energy.
Two variations of the drink have been seen so far. The first variant is bright green in color and contains a troll doll and several dice. The second is red in color, and its ingredients include ice cubes and plastic dinosaurs. Stan describes it as "if coffee and nightmares had a baby."