Tales From Gavagan's Bar by L. Sprague de Camp, Fletcher Pratt

Van with its eyes.
     
                  It was so quiet that he thought he'd slip out for a cup of coffee before phoning. But when he opened the door, with his reflexes not under very good control, the thing leaped down and was through it like a flash. Van expected it to run. It didn't; it came hopping along down the hall and then down the stairs, always keeping about the same distance behind him. Every time he turned around toward it, it would retreat, and then follow him again as soon as he went on. It seemed attached to him.
     
                  That made Van think—as well as he could think through the fumes of his hangover—that he might be having a case of heebie-jeebies and not really seeing this thing at all. So he decided to ignore it and started down the street. Then he began to notice other people when he passed them, they'd do a double-take and give a grunt or a squeak or something; and when he looked over his shoulder, there the thing was, coming along behind him; and other people seemed to be seeing it too. He began to walk faster and faster. Pretty soon he passed a girl who was going in the same direction he was; and when the animal hopped past her feet, she looked down at it and let out a good loud shriek. That did for what was left of poor Van's nerves, and he started to run.
     
                  You know how it is when anyone runs down the street. People look to see who's chasing who, and with a little encouragement, they'll join in. This time they had lots of encouragement, with that monster coming along behind Van in big jumps. Some yelled: "It's after him!" and, in about half a minute, he had twenty or thirty helpful citizens rolling along behind.
     
                  Sheer force of habit, he said later, brought him here to Gavagan's, and he dived in, to get away from all those people and that animal. You remember the day, Mr. Cohan?
     
    # ★ #
     
                  "Indeed and I do," said the bartender. "The poor felly came through the door there, like one of them fancy ice-skaters you see in the show, and stood hanging onto the bar. 'It 's brandy you need, my lad,' I said, and poured one for him while the rest of them people come milling around, some of them inside and some out, after this animal. But no animal did they see, because none had come in with him. All they saw was Mr. Van Nest having a drink of brandy and his hand shaking. Some of them said it got away over the roofs; but you're telling me that's not true now,- aren't you, Mr. Willison?"
     
    # ★ #
     
                  Another rye and soda [said Willison]. No, it certainly isn't true. The thing just disappeared. A couple of the people who had followed came in to ask Van about it, and they got to talking. Well, there's only one way you can conduct a conversation in a bar—that is, with a drink in your hand. Presently Van was drinking a Yellow Rattler and feeling better, and then they began treating each other and he felt better still, and the first thing he knew it was evening, and he'd spent the afternoon in here.
     
                  Now I won't say he was really drunk, not like he had been the day before; and besides, Mr. Cohan wouldn't permit it. But you can't work all day on brandy and Yellow Rattlers and nothing to eat without getting a little high. What did you say? Oh, he had a roast pork sandwich. So he had a roast pork sandwich and a couple more drinks, and went home and had a couple of nightcaps; and then I guess he was a little more than high. So he tumbled into bed; it was late when he got there.
     
                  When he came to, toward noon the next day, this spectral monkey-thing was there again. And this time there was another monster with it, a thing like a lizard with a long tail and thin fingers and something that looked like a big ruff around its neck, as you sometimes see in old ance stor portraits. It was a dark maroon