Cioccolata and Secco are tertiary antagonists in Jojo's Bizzare Adventure: Golden Wind. They are one of the last major fights of the part and are hands-down my favorite JJBA antagonists.
Their relationship is interesting and terrifying - and pretty much canonical. Not only are they partners in battle, but are also confirmed to have a close (and sometimes almost 'romantic' in their own fucked up way) relationship outside of their life of organized crime, spending more time on Cioccolata's... 'personal projects' than they seem to on being of use to the mafia at any given time. Diavolo (the Boss at the time) even goes to explain how the only reason he kept the two alive were for dire last-resort situations (due to Cioccolata's nature, his disregard for civilian life and well.. just everything about him).
These personal projects can be summed up into two categories: medical malpractice and snuff films. Cioccolata has a certain fascination with the human body, it's limits, and others experiencing their own death - and an obsession with capturing these on film. He has no regard for other human life (which is amazingly reflected in his stand's ability) and cares for no one except himself and his loyal 'dog' Secco, whom he is shown to care deeply about. He has a long history of illegal medical activity (missdiagnosing healthy patients in order to research on/kill them, limiting anesthesia to wake patients up and witness their reaction to their own surgery/death, and luring elderly patients into suicide to document it on film). He was eventually caught, but was picked up by the mafia where he and Secco obtained stands. He is also shown to have so much knowledge of the human body and it's intricacies that he is able to take apart and sew back his body in order to survive dire combat situations.
Pretty much nothing is known about Secco... like at all. We are told he was a patient of Cioccolata's and for whatever reason was spared by him and taken in as an assistant to video tape his victims. Secco is shown to be very loyal to Cioccolata and keen on following his lead. He is also shown to be what I hate to - but can only describe as - absolutely insane and not quite all the way there. He is amazing in combat, and excels at utilizing his stand to it's full potential, but seems to lack a lot of social and literacy skills. He also acts very animalistic, and is seen moving on all 4s, catching 'treats' with his mouth, and cleaning himself with his tongue.
Their relationship as unit is just as it looks - very strange, even for Jojo standards. A sadistic twisted doctor and his (also sadistic) animalistic assistant who he treats like a beloved well-trained pet. Cioccolata even goes as far as to tell Secco he loves him when accepts his fate of dying at the hands of Giorno Giovanna. Secco is shown to dismiss and insult Cioccolata after his death - making fun of him for his confession and admitting he only did all this because Cioccolata was rich and was paid well by the Mafia. I believe this 'confession' by Secco is heavily up to intepritation - as even in private moments where he would not have to 'keep up the act' he is shown to worry, care for, and admire Cioccolata - constantly calling him for advice and feeling dejected when he does not hear back from him. he is also seen playing along happily with a voicemail from Cioccolata who is promising him treats and back scratches once this mission is over - also in privacy.
Cioccolata and Secco have some of the best stand chemistry in the whole series - one playing off the other in such a perfect way it does almost seem as if they were made for each other.
Cioccolata's stand is Green Day - a humanoid stand that emits a deadly mold that melts any living thing that moves lower, in any capacity, from the altitude it was at when the mold infected it. This mold is shown to be very fast-acting and sometimes extremely painful - and nearly impossible to avoid getting infected with, as the mold spreads invisibly through the air not only from Green Day, but also from any victim's corpse. This allows the mold to spread rapidly in higher populated areas. The only thing this mold does not affect are corpses (those that are dead prior to contact - dying of the mold allows your body to continue to spread it's spores) and stands.
However an aspect of Green Day and Cioccolata I rarely see discussed is the mold's ability to control limbs. When Cioccolata breaks himself apart in order to fake Giorno out he also uses his mold to animate his detached arm. This mold control allows enough strength and dexterity to deal a pretty hefty blow. He is also shown using his mold to be a makeshift cauterization of his wounds.
Secco's stand is much different, but acts as a huge boost to Green Day's ability. Oasis is a close-range stand that also acts as a suit for Secco (that weird body suit he's wearing? that's his stand! - which is also why he is the perfect combat partner for Cioccolata. He wears his stand which makes him virtually invincible to Green Day's deadly mold). His stand allows him to turn any solid surface into liquid which lets him sink structures, people, and to swim underground and through pretty much any solid surface. This ability also allows him to eat and then spit liquified pieces of the surface, which then harden into sharp deadly spikes that rain from the sky. His ability to soften the ground can also be used to bounce his elbows off the surface, letting him amplify the power and speed of his punches. He is also shown to be able to melt people if he is in close enough range.
As you can imagine the ability to surprise attack and 'sink' people goes hand-in-hand with Green Day's ability. If Secco manages to catch his target by surprise he can then force them to lower their altitude and, depending on the severity of the sinking, potentially kill them almost instantly with Green Day's mold. This coupled with the fact that he wears his stand as as a body suit makes Cioccolata and Secco one of the best stand match-ups in Jojo's - and one of the most intimidating duos in the whole series in my opinion.
His one big weakness is that his ability to track victims and other things from under the ground's surface requires an almost perfect sense of hearing - if this is compromised he is left unable to use his stand for mobility or target tracking at all anymore.
Just as a little bonus I wanted to share some interesting stuff I found while gathering images for this shrine!
Tadashi Harada is a Japanese hair and makeup artist that has done collabs with a lot of popular anime/manga - including jojo! Below are his renditions of Cioccolata and Secco as well as a group shot (side note: i LOVE the Bruno from this series).
And here is Secco as he appears in Jorge Joestar - I find this rendering of him particularly interesting. While this wasn't drawn by Araki the novel is backed by Araki - he even did cover art for it.
The original characters written by Araki already have a lot of kinky vibes and undertones, but this takes it to a whole other level. He is shown is what is pretty obviously bondage/bondage inspired gear and is wearng a gag shaped like one of his beloved sugar cubes. He is also in what is quite literally a gimp mask.
I have not read Jorge Jostar (yet! It's on my list after PHF and Jojolion!) - and am planning on expanding this section once I do and have more of an idea on what role these two play in the novel.