Author Appeal: Allred created this series as a love letter to pop culture from the 1930's to the 1960's.
Beatnik: Frank comes into conflict with a group of mutant beatniks many times. They eventually ally themselves with Frank and become The Atomics.
Beware the Nice Ones: Frank is a nice, sweet guy who would rather avoid getting into a fight. If you gave him an excuse, however, be prepared to get brutalized horribly. Frank was a hired killer in his past life and his old personality creeps up from time to time.
Body Horror: Frank is a reanimated corpse and looks it. Then we have the Circus ringleader who has horns, the Circus Muscle Man who has no flesh, The Puke who turned into a giant blob of vomit, Dr. Boifard who eventually evolved into a massive brain, and many more.
Brilliant, but Lazy: Frank is rather innocent but has an intellect close to Dr. Flem and Boifard. Unlike them however he would rather spend his time hanging out with Joe and often complains when his adventures make him work any harder than that.
Circus of Fear: The circus Madman briefly worked for. Many of them looked very freakish (see Body Horror above) and Frank suspected at least one of them of commiting murder. He turned out to be only partially right. It was someone in the circus but it wasn't the Muscle Man as expected. It was one of the acrobats.
City of Adventure: Snap City is the home of the main characters. It has aliens, mutant beatniks, and secret governments galore.
Civvie Spandex: Frank sometimes adds a leather jacket over his normal spandex costume. Like Animal Man it gives him pockets to keep stuff in, but it's mostly because Joe likes it.
A Running Gag is Frank owing Gale a jacket because he accidentally lost hers in his first adventure.
Cloud Cuckoo Lander: Madman himself is pretty odd but the universe he lives in is already pretty surreal so it might not be noticable upon first glance.
Early-Installment Weirdness: The first scene of the entire series features Madman ripping an eyeball out of a thug's head and swallowing it. He is shown coughing it back up once the thug and his partner leave but the character ended up going in a completely different direction. Allred himself mentioned that he hated that scene right after he wrote it.
Eldritch Abomination: Some have shown up with little explanation, making people go insane, giving them superpowers, or just generally being creepy.
Expy: The character Freakazoid! wears a costume that looks similar to one of Madman's earlier designs. The creators of that series apparently got Allred's blessings to do this but since Mike was never given much credit, it's is a bit of a sore spot.
The Faceless: For the first miniseries, Frank's face was never shown.
Genre Shift: Atomic Comics starts out...strange, but there is still some adventure to be had. By the end of it however, things get rather less...superheroey. For example, the last two issues of the series, while including Frank briefly getting charred by an alien, is ultimately about aliens dressed as girl scouts asking the Atomics to play at a concert on their home planet.
Incredible Shrinking Man: Frank used a shrinking formula to beat The Puke but accidentaly got some on himself, spending a brief storyarc trying to survive.
I Thought You Meant: When Frank first meets Joe's father, he briefly talks about his psychic powers. Joe's father responds with, "So tell me, can you control it?" An aghast Frank swears that he is a gentleman and would never do anything she didn't want to do. He then finds out that Joe's father was referring to the control of his powers.
Killer Yo-Yo: Frank uses a yo-yo filled with lead. It's a pretty devastating weapon.
Kirby Dots: If a machine is crackling with energy, expect this effect.
Man Child: Frank is very sweet and innocent and often enjoys playing with his yo-yo or other toys. In the past, he had tendencies of a Psychopathic Manchild if you threatened him too much or those he loves but those days are gone.
Occult Detective: He moonlights as a professional psychic, often lending his powers to help a detective agency in Snap City.
Off with His Head!: Dr. Flem, Madman's other creator, had to chop off his own head (long story) and now has it strapped to his neck. Yes, a decapitated character got better despite having a head that isn't completely attatched.
The Pirates Who Don't Do Anything: In Atomic Comics, though mostly towards the end, Frank does surprisingly little superheroing. He has a few enemies pop up now and then, but once Monstadt is defeated, there is very little adventure to be had.
Robot Buddy: Several since Dr. Flem enjoys building robots but the most common would be Astroman, Marie, and Warren. Marie and Warren are floating spheres with hands that are silent but have personalities all their own.
Robot Girl: Mechana, although she doesn't look quite as human as other examples of this trope.
Robotic Spouse: Astroman and Machina for each other in a rare robot-on-robot example. It should be noted that Dr. Flem's robots began creating robot companions for themselves.
The aforementioned Machina looks a lot like the robot from Metropolis and her lover, Astro Man, looks like a cross between Madman himself and Astro Boy. Considering Allred's love of all things pop culture, this is not an accident.
Ugly Guy, Hot Wife: Madman looks very much like a reanimated corpse, albiet a corpse that was handsome in his previous life. He has green skin, gray hair, a metal plate on his scalp, dark sunken eyes, and plenty of stitches. This doesn't stop the beautiful Joe from falling in love with him. She even mentions that she likes his scars, thinking they make him look dashing and rugged (although he really, really isn't)