Malifishmertz is the main antagonist of the Phineas and Ferb episode Excaliferb. He's the fantasy counterpart of Heinz Doofenshmirtz. He is an evil wizard who seeks to take over the Tri-Kingdom Area, and he is the nemesis of Parable the Dragonpus, the dragon counterpart of Perry the Platypus.
Malifishmertz first appeared when he casts a rain spell on the Tri-Kingdom Area. He then traps an arriving Parable in a wicker cage with the help from his assistant Lawn Gnorme, announcing that he has formulated a plan to bring canned meat monsters to help him take over the Tri-Kingdom Area; the rain has only been cast in order for the meat monsters to grow strong. When a group of heroes (consisting of Phineas, Ferbalot, Isabel, Bufavulous, and Baljeeetolas) go on a quest to find the legendary sword called Excaliferb created to defeat Malifishmertz, the evil wizard has sent a network of spies to find out what the group is up to.
As the group head closer to the sword, Malifishmertz casts an avalanche spell on them. Parable would later free himself from his cage with his fire breath and engages into a fight with Malifishmertz, but the evil wizard's sorcery proved to be more than a match against the little dragon. Having defeated Parable, Malifishmertz is about to finish him off until he it interrupted by the arrival of the group, who have gotten hold of Excaliferb and have now summoned an army of monsters to help fight against Malifishmertz and his meat monsters.
Despite his forces being outnumbered, Malifishmertz shows no fear and instead orders his meat monsters to attack while transforming himself into a multi-headed monster to combat against the heroes. Phineas later casts a potion on Parable, transforming him into a large dragon to fight against Malifishmertz in combat. Though Ferbablot managed to defeat the Meatlings by transforming himself into a Medusa-like monster to turn them into stone, the battle's aftermath was left undisclosed, as every time whenever Parable seemingly got the upper hand, Malifishmertz always strikes back, making it more difficult for Parable to defeat him.
However, in the end of the episode, Carl states that a peace treaty was drafted between both sides, and during the time, Malifishmertz ended up being locked on a stock. During a bonfire party for the heroes, Malifishmertz manages to break himself free from the stock, and since everyone is busy cheering, he takes the opportunity to escape, planning to fight another day in a potential sequel to the story.
- Malifishmertz is currently the only counterpart of Doofenshmirtz that came close to killing his nemesis.
- Unlike most of Doofenshmirtz's counterparts, which they are either a possible ancestor and/or an alternate dimension counterpart, Malifishmertz is considered to be a fictional fictional character, as Carl was reading a book to an ill Monogram during much of the episode. Also, unlike many of Doofenshmirtz's counterparts, Malifishmertz proves himself to be competent, though this may be due to his skills in magic.
- Malifishmertz confesses to have many irrational fears towards unicorns, whales, squid, Pegasus, barnacles and scorpions, and a mild anxiety related to girls. However, when Candavere (the peasant girl counterpart of Candace Flynn) appears behind him as a mutant containing all his fears while confronting Phineas and Ferbalot during the final battle, Malifishmertz doesn't show any fear on this, as he finds Candavere's mutant form to be extremely ridiculous rather than scary.
- Looking at the horns on Malifishmertz as well as his name and staff, it is possible that he is a parody of Maleficent.
- He is one of the three counterparts of Doofenshmirtz shown to be competent in doing evil (the others are The 1914 version of Doofenshmirtz and the 2nd Dimension Doofenshmirtz. Also, unlike many of Doofenshmirtz's counterparts (who are shown to be physically weak), Malifishmertz is shown to be physically strong, able to put up a nasty fight against Parable and making it more difficult for the latter to defeat him.
- Although at the end of the story, Carl mentions that Malefishmertz escaped to get revenge in a sequel to the story, no sequel episode was made before the series' end, leaving his fate unknown.