Frog-Man (Eugene Patilio) is a comedic superhero appearing in American comic books published by Marvel Comics. Created by writer J. M. DeMatteis and artist Kerry Gammill, the character's costume is actually borrowed from a previously existing villain named Leap-Frog created in 1965 by writer Stan Lee and artist Gene Colan. Frog-Man was first introduced in the comic book series Marvel Team-Up (a series focused on pairing Spider-Man with a different character each month) in issue #121, published in June, 1982 (with a cover date of September). The characters Eugene Patilio and Leap-Frog are both unrelated to the original Marvel villain called Frog-Man.

Eugene Patilio is the son of Vincent Patilio, who uses technology of his own design to commit crimes as the costumed villain Leap-Frog. After repeatedly being thwarted by heroes such as Daredevil, Spider-Man, and Iron Man, Vincent serves a prison term and retires the Leap-Frog identity, now ashamed of his criminal actions. To make his father proud and alleviate the man's guilt, 15-year-old Eugene decides to use the Leap-Frog costume and technology to perform good deeds as "the fabulous Frog-Man." Throughout his adventures, Eugene often endangers himself due to his ignorance of combat techniques and lack of skill in operating the frog-suit. Initially seeing Spider-Man as a potential rival, Eugene comes to admire and emulate the hero. At one point, Frog-Man forms a team called the Misfits alongside the mutant Toad and the teenager Spider-Kid, but the trio disbands almost immediately. Later, Eugene is a registered member of the Avengers Initiative and serves in a Kentucky-based team called the Action Pack, but is almost immediately captured and replaced by an alien impostor. Since returning to Earth and finishing college, Eugene now only occasionally dons his Frog-Man suit to act as a hero and spends most of his time working at Isaac's Oysters, a restaurant owned by Isaac Christianson (the hero called Gargoyle).

The character made his live-action debut in the Marvel Cinematic Universe television series She-Hulk: Attorney at Law (2022), played by Brandon Stanley.

In Daredevil #25 (1965), writer Stan Lee and artist Gene Colan created and introduced a criminal named Vincent Patilio who creates electrical "leaping coils" and becomes the costumed villain Leap-Frog. The villain appeared in a handful of stories and then made his final appearance as an active criminal in Iron Man #126-127, published in 1979. Three years later, writer J. M. DeMatteis decided to revive the idea of Leap-Frog but as a more comedic, light-hearted character, a would-be hero rather than a villain. Named "Frog-Man", this new character was introduced as Eugene's previously unknown son in Marvel Team-Up #121 in June, 1982 (with a cover date of September). The series Marvel Team-Up featured Spider-Man joining forces with one or more Marvel characters in each issue, and issue #121 paired the web-slinger with his longtime friend and occasional rival Johnny Storm, the Fantastic Four member known as the Human Torch. Frog-Man's first story was illustrated by artist Kerry Gammill who designed Eugene's civilian appearance. DeMatteis later referred to Frog-Man as one of his "all-time favorite" characters.

Frog-Man's first appearance establishes that Vincent Patilio is a widower with a teenage son, that he served a short prison term after the events of Iron Man #126-127 and was released on parole, and that he now regrets his actions as Leap-Frog. The story introduces Vincent's teenage son Eugene, who decides to adopt the Leap-Frog costume use it to defeat the villain Speed Demon, a task Spider-Man and the Human Torch are already attempting to achieve. After helping defeat the Speed Demon despite his ineptitude, Eugene declares himself "the fabulous Frog-Man."

Frog-Man's second story appeared in Marvel Team-Up #131 (1983), also written by J. M. DeMatteis and with art by Kerry Gammill and Mike Esposito. In the story, Frog-Man joins Spider-Man against a new villain called the White Rabbit, a woman whose costume and crimes take inspiration from Alice in Wonderland.

Frog-Man appears again in The New Defenders #131 (May, 1984), in a story plotted by his creator J. M. DeMatteis, scripted by Peter B. Gillis, and with art by Alan Kupperberg and Christie Scheele. In the story, Frog-Man remarks that he has only had two adventures and hopes to become a more impressive hero by joining the superhero group known as the New Defenders. Frog-Man then meets team members Beast, Angel, and Iceman. The same issue introduced a new, comical would-be villain known as the Walrus, a man who is given superhuman strength by "omicron rays" and then takes inspiration from his favorite Beatles song, declaring he now has the "proportional strength of a walrus" (a joke by DeMatteis on how Spider-Man is often described as having "the proportional strength, speed, and agility of a spider").

The Amazing Spider-Man #266 (July, 1985) presented a story written by Peter David and with art by Sal Buscema and Joe Rubinstein. In the story, writer Peter David mistakenly refers to Eugene Patilio as Eugene Colorito. The story also shows Frog-Man meeting the would-be teenage hero Spider-Kid and the mutant Toad, a former member of the Brotherhood of Evil Mutants. The issue ends with the three deciding to become a crime-fighting team called the "Misfits" (due to Spider-Man using this word to describe the trio). No subsequent stories are ever published featuring the Misfits as a team and Marvel information guides later clarify the trio disbanded almost immediately. In 1993, the April issue of Marvel Age #124 featured an April Fool's Day ad for a new Misfits team with a membership of Frog-Man, Squirrel Girl, Razorback, and 3-D Man.