Pennywise (first appeared in It)

Pennywise is mentioned in the following books:

The Dark Tower VII: The Dark Tower (Sep 2004)

In Dandelo's final moments, he bears a striking resemblance to a certain psychotic clown.

Joe staggered, waving his arms for balance and looking around at her. His upper lip rose, exposing his teeth—perfectly ordinary teeth, and why not? He wasn’t the sort of vampire who survived on blood. This was Empathica, after all. And the face around those teeth was changing: darkening, contracting, turning into something that was no longer human. It was the face of a psychotic clown.
- Part 4 / Chapter VI / Section 1

Mr Mercedes (Jun 2014)

Pete peered through the droplets of rain on the driver’s side window, not touching the glass. Lying on the leather driver’s seat was a rubber mask, the kind you pulled over your head. Tufts of orange Bozo-ish hair stuck up above the temples like horns. The nose was a red rubber bulb. Without a head to stretch it, the red-lipped smile had become a sneer. “Creepy as hell. You ever see that TV movie about the clown in the sewer?” Hodges shook his head. Later—only weeks before his retirement—he bought a DVD copy of the film, and Pete was right. The mask-face was very close to the face of Pennywise, the clown in the movie.
- Part 1: Det.-Ret. / Chapter 14

Dreamcatcher (Mar 2001)

When Mr. Gray takes Jonesy to Standpipe Hill in Derry to deliver his deadly infection into the water supply, the alien is incensed to find that the Standpipe no longer exists - it was destroyed in the great flood of 1985. A statue commemorates those lost in the storm.

The pedestal was drifted to most of its height in snow, but the top of the plaque screwed to the front was visible. Mr Gray fell to Jonesy's knees, scraped snow away, and read this: TO THOSE LOST IN THE STORM MAY 31, 1985 AND TO THE CHILDREN ALL THE CHILDREN LOVE FROM BILL, BEN, BEV, EDDIE, RICHIE, STAN, MIKE THE LOSERS' CLUB Spray-painted across it in jagged red letters, also perfectly visible in the truck's headlights, was this further message: PENNYWISE LIVES.
- Part 2 / Chapter 16 / Section 6

The Tommyknockers (Nov 1987)

When Tommy Jacklin travels to Derry, he has a vision of a clown in the sewers.

Tommy had begun to hallucinate; as he drove up Wentworth Street, he thought he saw a clown grinning up at him from an open sewer manhole—a clown with shiny silver dollars for eyes and a clenched white glove filled with balloons.
- Book II / Chapter 10 / Section 14

The Dark Tower III: The Waste Lands (Aug 1991)

Eddie and Susannah come across a damaged young man in Lud and note that he reminds them of, respectively, Ronald McDonald and Clarabell the Clown. In IT, George sees Pennywise in the drain and thinks that he looks like a cross between Bozo and Clarabell. King notes that if George had been alive a year later, he probably would have been more likely to relate him to Ronald McDonald.

Come on, you deucies!” a relatively young man snarled. He wore his blue scarf around his throat like a rally-racer’s ascot. He was bald except for two fluffs of frizzy red hair, one on each side of his head. To Susannah, this fellow looked like Clarabell the Clown; to Eddie he looked like Ronald McDonald; to both of them he looked like trouble: He threw a homemade spear that might have started life as a steel tableleg.
- Book 2 / Part V / Chapter 21

The Dark Tower VII: The Dark Tower (Sep 2004)

Bryan Smith is a fan of the IT miniseries, and tells Stephen King so.

Smith took another bite, a humongous one this time. “I liked the show they made about the clown, too! Very cool!”
- Part 3 / Chapter II / Section 7

The Dark Tower VII: The Dark Tower (Sep 2004)

The sköldpadda tumbled to the red rug, bounced beneath one of the tables, and there (like a certain paper boat some of you may remember) passes out of this tale forever.
- Part 1 / Chapter I / Section 7