Tracer Bullet is a rarely-seen alter-ego of Calvin's.
The character, a private investigator based on any number of film noir and detective novel clichés, makes his first appearance in a story arc in which Calvin gets a bowl haircut courtesy of Hobbes. When Calvin was forced to wear a hat to cover his bad haircut, the alter-ego was born, and he would appear in a total of three story arcs.
His rate is $50 a day plus expenses. However, in his first introduction he claims business is poor, as he has "an office on 49th Street and a nasty relationship with multiple collection agencies". Tracer Bullet is a skilled marksman, and also claims "if business were as good as my aim, I would be on Easy Street".
Bill Watterson is quoted as saying:
"Tracer Bullet stories are extremely time-consuming to write, so I don't attempt them often. I'm not at all familiar with film noir or detective novels, so these are just spoofs on the clichés of the genre. Cartoonists don't use black much anymore (the eye, being lazy, is attracted to empty white space, especially when the panels are so small), and we miss some dramatic possibilities that way."
While Tracer Bullet's narration usually dominated the individual strips he appeared in, his monologues tended to only provide exposition or reflection on previous action. The actual storyline generally would progress through comments by Calvin or any associated characters, almost always in panels featuring the real world of Calvin, not the imagined world of Tracer Bullet.
- Tracer Bullet's first appearance was in the story arc featuring Calvin's bad haircut. However, he only appeared in 3/4 of one strip. This arc was reprinted in Something Under the Bed Is Drooling.
- Next, he was featured solving a case (math quiz), interrogating the "Derkins dame" (trying to copy off of Susie's paper), learning that Derkins had been "shut up for good" (Susie didn't allow Calvin to cheat) and getting mugged on the way to a tavern (stopped by Miss Wormwood on the way to the water fountain). He then "solved" the case by going to the archives and learning of an extremely suspicious "Mr. Billion". So Calvin wrote 1,000,000,000 as the answer (when the real answer was 15, according to Susie, who happened to be right). This arc was reprinted in Scientific Progress Goes "Boink".
- His final appearance was in a week long arc; Calvin's mom came across an overturned table and broken lamp, and blamed Calvin for it. She (Brunette) went to Calvin's room (came to Bullet's office with a case), forced him to the living room, and began demanding that he explain himself ("The dame was hysterical. Dames usually are."). Calvin began looking for clues, and his mother kept asking him what he had to say for himself (Brunette readied a gun at the back of Bullet's head; Bullet realized that he'd been set up- the client didn't want the case solved- she wanted it blamed on Bullet!). Calvin drew his dart gun and shot a few rounds (Bullet shot and missed Brunette), then was stopped and reprimanded by his father (accosted by the dame's hired goon). In the end, it turned out that Hobbes had broken the lamp, throwing a football in the house. This arc was reprinted in Attack of the Deranged Mutant Killer Monster Snow Goons.
- All of the Tracer Bullet arcs begin with a reference to guns and alcohol;
- "I've got eight slugs in me. One's lead, and the rest are bourbon. The drink packs a wallop and I pack a revolver."
- "My buddies travel light, and they're fun to have around. One travels in a holster, and the other in a hip flask."
- "I keep two magnums in my desk. One's a gun, and I keep it loaded. The other's a bottle and it keeps ME loaded."
- Tracer Bullet has three guns, a .38 revolver (Smith & Wesson Model 10), and .45 automatic (an M1911A1), one strip also implied he owns a .44 Magnum (most likely a Smith & Wesson Model 29).
- Tracer Bullet is most likely named after a type of ammunition that can be seen by the naked eye.