Negaduck (tronsplit version) is the first and original form that appears in the titular episode “Negaduck”. He was a one-shot character who was later replaced by the Negaverse version of Negaduck. Official Disney merchandise refers to this version as “Negatron”.
When Megavolt's tronsplitter accidentally hits Darkwing, he is separated into two versions of himself. One composed entirely of Positrons (good energy) and another made entirely of Negatrons (evil energy). Negatrons and Positrons are explained as “the building blocks of good and evil” and seemingly play a role in the overall morality of a character.
Nega-Darkwing retains the same appearance as regular DW, except he has visibly thicker eyebrows (which allows the audience to differentiate between the good and evil halves). Throughout the episode, Nega-Darkwing antagonizes the citizens of St. Canard through random acts of violence and crude behavior (such as whipping out a shotgun in a crowded movie theater and shooting at the bunnies on the film projector).
Later he teams up with Megavolt who he sardonically refers to as “dad” due to the fact Megavolt 'created' him with the tronsplitter. This alliance turns out to be a ruse, as Nega-Darkwing simply wanted access to the tronsplitter so he could destroy it, preventing any chance of him being re-merged with his good half.
During the scuffle between Nega-DW and Megavolt, the evil twin is once again hit by the tronsplitter. Megavolt explains that “Negatrons alone can't be split or merged” and so instead he is 'galvanized' into a being of intense pure evil energy, referring to himself as “Negaduck”.
Unlike his previous form, Negaduck only cares for mindless wanton destruction and uses his powers to decimate the city of St. Canard. Eventually he is challenged by the galvanized version of his good half (Posiduck) and the two are finally re-merged with the tronsplitter during their fight.
This version of Negaduck is never seen again in the series. Creator Tad Stones has stated in several interviews that the writers wanted to bring him back as a reoccurring character. However they could not repeatedly tronsplit Darkwing, so instead they created a second version which has come to be known as the 'regular' Negaduck from the Negaverse.
Because Negaduck is composed entirely of Negatrons, he is only capable of expressing acts of pure evil. He is excessively violent to the point where he threatened Gosalyn after she broke his statue. He has no concern for the safety of others and relishes in their pain and suffering.
The galvanized version of Negaduck has superpowers in the form of negative energy that resembles static electricity. He is able to destroy everything around him quite effortlessly. The tendrils of energy will zap and lash out at anything in close proximity and he is able to focus his powers by charging up balls of negative energy that can be thrown at specific targets.
He appears to be evenly matched with Positron (good) energy as neither was able to overpower the other.
“Give me back my face, you're getting it ugly!” - Nega-Drake talking to his Positron half
“Nobody's gonna put me back together with a namby-pamby goodie two-shoes like you!” - Nega-Drake talking to his Positron half
“I am the most fiendish terror that flaps in the darkest night, I am the skunk that pollutes your air! I am Negaduck!” - Negaduck, after being galvanized by the tronspitter
Megavolt: Let's go do some major crime!
Negaduck: Crime? Who cares about crime?! I'm into wanton, mindless destruction! Now, to lay waste to St. Canard… just for the fun of it!
Megavolt: Ingrate! You're no son of mine!
Megavolt is responsible for the creation of Negaduck and views him as a 'son'. He was more than eager to team up with Negs to commit crimes together but was quickly rebuked by the galvanized version. Megavolt joins forces with Gosalyn and Launchpad to re-merge Darkwing back to his normal self, explaining to Gos “if he destroys St. Canard, there'll be nothing left to rob!” After Darkwing is re-merged he attempts to double-cross them but instead he is accidentally zapped with his tronsplitter and ends up with two heads attached to the same body.
Unlike his regular self, this version of Darkwing displays no affection for Gosalyn. When he discovers she broke his favorite statue he threatens to ground her into hamburger and tells her she'll spend the rest of her life paying for her carelessness. Later when Gos attempts to stop galvanized Negaduck, he swats her away without a single glance that throws her backwards and almost injures her.