Cecilia is the primary antagonist of the All Dogs Go to Heaven: The Series episode "Haunted Is as Haunted Does."
She is a female ghost who pushes her timid brother Sebastian around. She is capable of scaring anyone, including dogs (especially Itchy), and attempts to shape her brother up to scaring three trespassing punk teenagers.
One time, when she does not manage to scare Charlie, she summons Scabwart to scare him.
Eventually, when Sebastian, sympathizing with Itchy, sees him and Charlie dangling by the tree, he suggests helping them. When she refuses, he scares her into changing her mind. After this, she praises Sebastian for his gumption, and Itchy gives them the address of where to move: the gardener's cabin.