- Author Existence Failure: In the Japanese dub of the live-action film, this was the final voice acting work for El Super's voice actor, Tetsuo Goto (better known for anime fans as Gowasu) before dying at November 2018.
- Creator's Pest: Ibañez wasn't very fond of Irma, and she stopped appearing altogether the moment he regained control over the comic.
- Executive Meddling: A lot in the early years - the Bruguera company even tried to "steal" the characters from Ibáñez and give them to other authors a couple of times. He also had to deal with the Francoist official censorship, which was pretty hard at suppresing Toilet Humor and anything that denoted "subversion". For instance, the cops are called "gendarmes" and their uniforms and cars do not look anything like the Spanish police ones of the timenote ; when a character made any reference to the Spanish Civil War it either disappeared or was changed to "the '14 war", a war in which Spain never took part, and so on. One character of 13 Rue del Percebe (another comic strip from the same author that sometimes Cross Overed with Mortadelo y Filemón), a parodic Mad Scientist that built monsters for a living, was eventually written out and substituted by a tailor because the dead-hard Catholic government thought that "Only God can create life". This is also why women do not appear at all in late 50s strips - each time Ibáñez drew one, the censors eliminated so much curves that it ended looking like a broomstick.
- Even some dialogues had to be changed because of censorship. In one instance, Mortadelo sees a monster, and runs to Filemón in panic, trying to alert him. He tries to say "¡Un monstruo!" ("A monster!") but he's so scared that he can only babble: "¡Un mo... un mo...!". Filemón thinks he's trying to say "un moco" ("snot") and says "Si tiene un moco, suénese" ("If you've got snot, blow your nose") as he produces a handkerchief. "Moco", though a quite colloquial, innocent word, was such a profanity for some censor that Filemón's answer was rewritten as "¿Un mono? Aquí no hay monos" ("A monkey? There are no monkeys here"), making the gesture of producing the handkerchief completely absurd.
- Recycled Script: Post Seasonal Rot, several albums have been accused of this. For example, "El tirano" being a remake from "Objetivo: Eliminar al rana", "La MIER" from "Cacao espacial"...
- Same Language Dub: Unlike previous films exported to Latin America, when the Spaniard voice acting was kept, the most recent movie (Mortadelo y Filemón contra Jimmy el Cachondo) was redubbed into Mexican Spanish, in this case because the sole name of the titular bad guy, Jimmy el Cachondo, was changed in the Mexican dub, because Cachondo in Mexican Spanish means "horny", while in Spain it means "funny" instead. In Mexico it was renamed as Jimmy el Locuaz (Jimmy The Wacko).note
- Unintentional Period Piece: Most of the stories released in the XXI century could be considered this, as they tend to be themed after an important event happening at the time. A notable example from The '90s, before the aforementioned trend started, is "El quinto centenario" ("The fifth centenary"). It's themed, as its name suggests, after the fifth centenary of the Discovery of America, with the protagonists time-travelling to join Christopher Columbus' crew. Many jokes are lost to modern readers. To start with, most important characters in the past are drawn like important politicians from the year the comic was released. Some characters were drawn like politicians who would still be recognisable or relevant years later (such as future Prime Minister José María Aznar or Cuban leader Fidel Castro), others... not so much (even the then Prime Minister Felipe González, still known nowadays, can be hard to recognise due to how he's drawn). The story ends with a parody of the 1992 Universal Exposición of Seville which, as refering to a one-time event which only lasted 6 months and was located in a single city, is as accesible to modern readers as you would expect.
- Write Who You Know: One of the companies that has employed the TIA the most (and by extension, M&F) in several books and short stories is Ibáñez's publisher, Editorial Brugera (later known as Ediciones B). Some of Brugera's personnel became recurring characters with defined personalities in those stories; the head editor, for example, is a mischievous, millionaire Femme Fatale with a penchant for long walks atop her pet elephant.
Trivia / Mortadelo y Filemón