W.C. Fields is supposed to have said, "Never work with children or animals," but he could never have imagined the scene-stealing ability of a charming adult woman like Jamie Ann Romero playing the role of a dog in Sylvia. Sylvia is a stray brought home from the park by Greg, who's going through a midlife crisis. She's cute and appealing, and she worships him from the get-go, so naturally Greg becomes obsessed with her — to the distress of his wife, Kate. Sylvia can seem sensitive, thoughtful and empathetic, but she can also be a manipulative nuisance, peeing on the carpet, chewing Kate's shoes, humping a visitor's leg or snarling furiously at a passing cat. Romero threw herself into all these actions with relish, swinging enchantingly from mood to mood, and her playful presence made the entire Lone Tree Arts Center production magical.