Without a doubt, Calvin and Hobbes has been a one of the most successful comic strips of all time. Despite Bill Watterson steadfastly refusing to sell out to any licensing or merchandising opportunities for his creation, it remains one of the most well-known strips of all time, thanks mainly to the wonderful affect that Calvin has on readers.
Throughout the comic's run from 1985 to 1995, Calvin went on many fantastical adventures, often in the guise of one of his many alter egos. The boy has imagined himself in many different roles over the years, some as generic monsters or creatures, others as fully fleshed-out characters who have made multiple appearances in the strip's history.
The Incredibly Annoying Human Echo
Calvin's goal seems to be to annoy everyone around him at times, and one of his "alter egos" that he uses to pull this off is one known as the Incredibly Annoying Human Echo.
While this character has only made a few appearances, it still left quite an impact, especially in the other characters' methods in stopping Calvin's fun. For example, Calvin's Dad tries to make him repeat a line that makes him lose all deserts for a week, while Hobbes reads from a long, complicated book to confuse Calvin. It might be one of Calvin's more annoying alter egos, but it's one that many parents have probably dealt with, making it instantly relatable.
Calvin The Bold
A big way to sum up Calvin as a character is that he's really arrogant and thinks very highly of himself, leading to creating other egos for himself to reflect this.
One such alter ego was "Calvin the Bold," which was essentially just Calvin, except he answered only to the sobriquet "Calvin the Bold." This title quickly got on the nerves of both his parents and Miss Wormwood, so much so that Calvin's dad quickly brings him back down to reality by dubbing him "Mud." While not as memorable as Calvin's other alter egos, it's a good one to look at when annalizing his character as a whole.
The World's Most Powerful Computer
Calvin's love for sci-fi and fantasy has led to many comics about space and robots, leading to him to cosplay as an odd entity known as "The World's Most Powerful Computer." Using nothing more than a cardboard box decorated as a computer, Calvin walked around and told people to ask him questions.
Of course, no one took him seriously. Hobbes simply asked why the World's Most Powerful Computer wore sneakers, and Calvin's mom kicked him back up to his room with a clear use of good parenting when she figured out he didn't clean his room. As such, after it's initial appearances, this alter ego was never seen again. At least it showed off Calvin finding another use for cardboard boxes.
Captain Napalm
Calvin employed the use of many one-off alter egos through the course of the strip's history. One of these one-offs was another superhero identity from his comics called "Captain Napalm."
Exactly what kind of superpowers Captain Napalm has is left unclear, for, when Calvin ducks into a closet to become this character, he gets stuck in the closet and calls for his Mom to help get him out. It may seem like an insignificant one-off, but it would only be the start to Calvin's superhero exploits, as he would one day become the hero known as Stupendous Man.
Monsters
Many kids often imagine themselves as monsters rampaging through fictional towns, and Calvin is no exception to this fantasy. There have been many strips in which Calvin has taken up the guise of a monster, whether it be a giant or a Godzilla-type.
While he often uses these in his own personal fantasies, there have been times when he becomes a monster and goes after his enemies, most notably his parents. Unfortunately, these incidents have often led to him getting in trouble, leaving it better and more memorable for him to keep giant monsters to his own fantasy towns.
Suzie's Husband
A hilarious running gag throughout Calvin and Hobbes is Calvin's ongoing feud and hatred of Suzie. Despite this hatred of her, he still plays house with her from time to time. In these instances, Calvin often plays the role of Suzie's husband, and most of the time that role comes with being subservient to her character.
Naturally, being the kid that he is, this has infuriated Calvin multiple times, leading to very few strips involving him playing with Suzie. It's much funnier to see the two act as enemies anyway.
Dinosaurs
Some of Calvin and Hobbes' funniest comics involve one of Calvin's many interests: dinosaurs. In fact, Calvin is so interested in dinosaurs that he sometimes imagines himself to be one. Many of the strips that depict this show him as a fearsome carnivore like a T. Rex going after meek and innocent prey, either other imagined dinosaurs or even people in a town
These of strips really show off how much Calvin likes dinosaurs and how cool he thinks they are. Unfortunately for him, sometimes he gets a little carried away, leading to big chases between him and someone he's tormented as a dinosaur, usually either his mom or Hobbes.
Tracer Bullet
One of Calvin's darker alter egos is the grim and gritty private eye known to the world as Tracer Bullet. Obviously inspired by old detective films, the character attempts to solve mysteries that Calvin encounters.
It's no surprise that many of these "mysteries" are caused by Calvin or Hobbes in the first place. In his fantasy, Calvin plays this up as a set-up by people and tries to gun them down with his dart gun, which never works out for him. However, Tracer does seem to always come up with an answer to the cases he must solve, even though most of the time he comes to the wrong conclusion.
Stupendous Man
Calvin's love for superheroes has led to him becoming one himself. After his mom makes him a costume, he has multiple adventures as the champion of freedom and liberty, Stupendous Man.
Of course, since his secret identity is Calvin, Stupendous Man's foes include the likes of Suzie, Rosalyn the babysitter, and Calvin's mom. Stupendous Man also battles the tyranny of elementary school over the course of multiple arcs.
Unfortunately, Stupendous Man, by Calvin's own ission, has only ever achieved moral victories, which is not really a good record for the hero. However, that doesn't prevent his exploits from being hilarious.
Spaceman Spiff
Who else? By far, Calvin's most iconic alter ego is the space explorer who travels the stars in a little red flying saucer. That explorer is, of course, Spaceman Spiff. Spaceman Spiff is Calvin's earliest and most frequently occurring alter ego as he flies around the galaxy searching for weirdness and avoiding hostile aliens that want to blow him to pieces.
Unlike Stupendous Man, Spaceman Spiff actually achieves some victories, albeit unintentional victories. But it's Spiff's relentless pursuit of the strange and unexplained all over the galaxy that really makes him one of the greatest aspects of this beloved comic.
