In the Negaverse, NegaTaurus Bulba and his crew actually took NegaGosalyn under their wing, they were a sabotage organization trying to prevent terrorism and after they killed her evil grandfather who made a dangerous machine and even abused her, they destroyed the weapon and took her with them. But then Negaduck came to take the said weapon, not knowing it had been destroyed, and killed Bulba (for nothing then) while he was trying to protect NegaGosalyn, as Negaduck was sure she knew how to activate it. When he found out he did all of that sgit for nothing, he still kidnapped her thinking she might know over scientific stuff and might be useful for the future (and he needed a slave anyway, and what better to corrupt a child, it's canon he loves it XD), and still made the building of the organization explode in order to feel like he didn't come for nothing, killing them all... except Hammerhead who survived (so no no Clovis X Hammerhead in the Negaverse as she dies even before they really talked to each other, like their pilot verse they barely talked to each other), just losing an arm, a horn (those 2 would later be replaced by the Negaverse version of FOWL, which here is normal verse’s SHUSH equivalent, as agent NegaSteelbeak used to be a college classmate who took pity of him and did that expecting nothing in return) and an eye.
Since then, he got determined to find Negaduck in order to avenge his colleagues (especially his boss as in this Negaverse they were exes who had used to be in love and even after the breakup remeained in very good terms) and his missing parts, and to take back NegaGosalyn (not aware she would later be adopted by the Friendly Four), following him everywhere even in the other verse as soon as he would learn about its existence. At times he would work with Darkwing Duck but vengeance being implanted very deeply in him and being hothead, he is generally a loner, especially as he hardly can stand the other Gosalyn, too much of a brat to him contrary to “his” Gosalyn.
So at times he would cross paths with his normal verse equivalent and he would being very horrified to see he is a mob boss (everything he had always fought against !) and quite confused/surprised to see he is with Clovis (and later EVEN MORE WHEN CHLOE WOULD BE BORN ! YEAH ESPECIALLY CHLOE SOMETIMES HE IS TOUCHED TO SEE A LITTKE GIRL WHO LOOKS LIKE HIM THEN HE SEES SHE IS AN EVIL BRAT AND REMEMBERS SHE IS NOT REALLY HIS BUT STILL THE SITUATION IS VERY HARD SOMETIMES HE WISHED HE HAD STOLEN HER TO GIVE HER A PROPER EDUCATION AT LEAST THE WAY HE SEES IT), which would sometimes give him regret like "Shit I hardly talked ta da Negaverse Clovis, guess I should'sve talked ta her more, I missed the opportunity ta have the love of my life and have a kid. But either way she'd be dead by now, so at least I’m not sad. Maybe empty, but sad. Woah that’s deep.” He and Hammerhead would never really dare to fight, both being way too weirded out at the idea to fight their mirror reflection, so they would just stand there criticizing each other or even chatting nonchalantly.
NegaHammerhead Hannigan is as hot-headed, coleric and grumpy as regular Hammerhead Hannigan, except he is a good guy with a sense of justice, hating criminals (not resisting at the idea of beating up some of them if he can), not being able to do a fraud at all (like if the subway machine doesn’t want its ticket, he would never dare to jump fence), polite if you’re polite with him and loving nice kids like NegaGosalyn, and even if he dislikes agitated kids like regular Gosalyn, he would just grumble, he would never hurt one. He also used, like Hammerhead, to care about his appearance and to be very classy with expensive suits and shaving, but since the accident, it doesn’t really matter anymore, not only his selflove got wrecked as he became crippled, but vengeance replaced it as his friends and colleagues died, as he almost died too and as a little girl got kidnapped. Appearance has just become a secondary matter now. Also, contrary to regular Hammerhead, he is still slightly (EMPHASIZE “SLIGHTLY”) more effeminate, regular Hammerhead hides it under the traits of a gruff boss not to be mocked or questionned about his role of gangster as it’s quite a macho work field, while NegaHammerhead, having always worked with people he was comfortable with (until they DIED) never had to hide it.
EHMARGERD ! I TRIED SHADING WITH FELT-TIPS FOR ONCE ! It looks shitty and barely visible on the pants and boots EXCEPT FOR THE BIONIC ARM I’M PROUD OF THIS ONE PART OF HIM Also a little thing I wanted to try : some Yin Yang effect with his normalverse self who has a white tie and a black shirt and he who has a black tie and a white shirt. Silly but I like having come up with the idea.

Darkwing Duck and Hammerhead Hannigan © Disney
NegaHammerhead Hannigan, drawing, idea and theories © me