Spider-Man: No Way Home provided fans with perhaps the greatest Spider-Man guest appearances of all time. Though Spider-Man plays a major role in several major Marvel Comics crossover events, including those that inspired MCU movies, his popularity leads to him making a lot of guest appearances in comics that don't seem necessary at all.
The guest appearance serves as the cornerstone of the Marvel Universe, building out continuity and connections, but it's not always worthwhile. Spider-Man's most egregious guest appearances come in comics where it's clear his iconic status is being leveraged to boost sales. Sometimes his guest appearances range from a small cameo to a big part in the story, but they always leave the reader questioning the purpose.
Fantastic Four #36
Spider-Man and the Fantastic Four share strong connections in Marvel Comics going back to The Amazing Spider-Man #1, but not every appearance possesses the same importance. Fantastic Four #36 features a cameo from Spider-Man where only his arm is seen, making it easily among his oddest appearances.
The cameo provides some humor during a battle with the Frightful Four but seems odd in light of the fact that the Avengers and X-Men both feature in a party scene where Spider-Man sneaks a piece of cake.
Alpha Flight #1
Comic book covers used to often feature images or plot elements that didn't actually occur in the comic. Few rank as high as Alpha Flight #1, which depicts Spider-Man on the cover with many other iconic Marvel superheroes like the Fantastic Four. Spider-Man appears nowhere in the comic book itself.
Bait and switch comic book covers seem a bygone relic in modern comics, but the practice was once much more prevalent and Redditors identified numerous examples where it continued well into recent times.
Daredevil #1
An even more egregious cover stunt involves Daredevil #1 from 1964, among the most important Marvel Comics ever. Though Daredevil eventually became one of Spider-Man's best allies in the comics, Spider-Man only appears on the cover here and strictly in the context of selling a new hero to the burgeoning Marvel readership.
Spider-Man properly met Daredevil in issue #8, which also introduces Daredevil's iconic red costume. The two remain close friends and likely team up in the MCU as No Way Home introduced Matt Murdock to the franchise.
Avengers #3
Marvel Comics fans longed for Spider-Man to join the Avengers for years, and he did eventually join one of the best Avengers rosters in the comics in the 2000s. But he only guested in the book prior to that, including a frustrating cameo early on in Avengers #3.
Iron Man meets Spider-Man for the first time as he goes through New York City looking for the Hulk. The sequence only lasts a few panels, though it does serve to further integrate the brand new Marvel Universe.
Foolkiller #8
Spider-Man appears on the cover and in the story within Foolkiller #8 from 1990, but this guest appearance serves as a good example of why they don't always work. Spider-Man features prominent on the cover and essentially takes over the story, with the POV shifting to him at the expense of Foolkiller himself, who becomes a spectator in his own comic.
The series ended a few issues later and Foolkiller remains securely in obscurity among the lamest Spider-Man villains, but this issue echoes a common occurrence with Spider-Man used to boost sales on flagging titles, especially in the 1990s.
Transformers #3
Marvel Universe characters routinely appeared in licensed comics based on toys in the 1970s and 1980s, though that led to headaches. It also led to head-scratching, especially when Spider-Man appeared in Transformers #3. He plays a big role in the story, covering the Transformers for The Daily Bugle, but it makes no sense.
His function in the story clearly seeks to boost the then-new series sales, but it was unnecessary given how popular the transforming robots proved. Spider-Man never appeared in Transformers comics again.
Excalibur #8
Spider-Man appears in the background of a panel buried deep within Excalibur #8 from 1989, and though it's fun, it serves little purpose. Spider-Man cameos along with Doctor Octopus as Brian Braddock, Captain Britain, struggles with losing his powers. The guest appearance likely goes by most readers on the first look.
This appearance disappoints in its brevity, though it's also a shame that Alan Davis, the regular Excalibur penciler at the time and among the best X-Men artists ever, missed this chance to draw Spider-Man. Though, guest artist Ron Lim rendered a great version of the Wall-Crawler in the comics, especially in The Infinity Gauntlet.
Excalibur #53
Excalibur #53's Spider-Man guest appearance makes more sense given his connection to Captain Britain, but his role in the book serves only one purpose. The character's oversaturation in 1992 gets called out in a meta way by Spidey himself when he says "That's right, it's me! Five monthly titles of my own weren't enough so now I'm taking over this one!"
His appearance in the book does connect back to Captain Britain's first ever appearance in American Marvel Comics, Marvel Team-Up #65. He teamed up with Spider-Man and the two actually shared an apartment in New York City for a brief time.
The Sensational She-Hulk #3
The Sensational She-Hulk #3 offers another cover that comments on its own brazen attempt to boost sales. She-Hulk introduces Spider-Man as the obligatory guest star, a fourth-wall-breaking insight into the Marvel tradition to establish characters and then swiftly integrating them into the large universe within a few issues.
The meta-commentary works in this case though. Comic book fans know She-Hulk established a meta-style early in her series that the new MCU live-action show emulates. That possibly means Spider-Man appears as well, though it's a long shot.
Justice League Of America #103
Marvel and DC 'cameo' the other company's characters all the time in sneaky visual gags or references, but Justice League of America #103 represents perhaps Spider-Man's strangest guest appearance. A man in a Spider-Man Halloween costume fights Batman for several pages, going far beyond a cameo and far beyond a subtle nod that would escape a copyright strike.
Spider-Man appears with a version of Thor as well as Captain America in the story, who wields a shield made from a trash can. The Justice League handily defeats the imposters before moving on with the story.