""Particular, huh?" said Mr. Willoughby. "And you're a hell of a looking object to be particular. Well, try this, then." He emptied the water from the saucer and put in a little beer. The cat made short work of the beer.
Mr. Willoughby sighed and filled the saucer with beer. He stood watching while the cat drank most, not quite all, of the beer and then lay down and this time it closed its eyes. It stretched voluptuously, as only cats can stretch..
Mr. Willoughby frowned at it, then went to the bookcase and got himself a book, sat down to read it and to sip his own beer. By eleven o'clock his beer was gone and his eyes were getting heavy. He put the book back. He leaned down to stroke the cat and found that its fur was sleek and dry.
He said, "Sorry, Cat. That's it.' He carried it over to the window and put it out on the roof. He undressed and went to bed. The beer and the reading had made him sleepy and he went to sleep immediately.
He wakened early, before the alarm went off. The room was gray with dawn and there was something heavy on his feet. He looked down and saw that it was the big black cat. He thought, I forgot that the bedroom window opens off that roof too. Damn.
He moved his feet and disturbed the cat; it looked at him reproachfully with yellow possessive eyes."
The Office, by Fredric Brown (copyright 1958; quote is from pages 50-51 of the E.P. Dutton & Company, Inc. First Edition hardcover).