Noah Haidle’s 2004 dark comedy concerns a precocious preschooler, Lucy, whose divorced mother neglects her, whose babysitter ignores her, and whose father is nowhere to be seen. So Lucy invents an imaginary friend, Mr. Marmalade. Problem is, he’s an overworked cocaine addict, emotionally distant and prone to unpredictable rages. Alternating scenes of daily life with Lucy’s increasingly dark fantasies–at one point she pretends to marry Mr. Marmalade, with dire results–Haidle creates a world both sad and funny. Dave Whalley’s low-budget production for Chemically Imbalanced Comedy throws the focus on Haidle’s strong dialogue and character development and on the comic gifts of his cast, especially Laurel Schroeder and Marz Timms as Lucy and her unsupportive friend. –Jack Helbig a Through 4/29: Thu-Fri 8 PM, Sun 5 PM, Cornservatory, 4210 N. Lincoln, 773-865-7731, $15.