The symbiote Carnage has a long history of doing horrible things to people, but nearing the top of the list is the time he infected Peter Parker and Mary Jane's infant son, turning the boy into Kid Carnage.
Even though this took place in an alternate future, it still introduced the concept of the symbiotes having an effect on the children of their former hosts. In some ways, Benjamin Parker was the precursor to Eddie Brock's son, Dylan, and all that he would go through when he first encountered the symbiotes.
Carnage had been a prisoner of S.H.I.E.L.D. for some time before acquiring a new host. But this version proved to be even more ruthless and aggressive than Cletus Kasady was, kidnapping Peter Parker and his infant son, Benjamin. The new Spider-Girl, May Parker, went after them, managing to track Carnage down and pluck her baby brother from his clutches. Unfortunately, Carnage had plans for the infant Parker and infected the child with his symbiote, transforming Benjy into Kid Carnage.
Kid Carnage then attacked Spider-Girl without the restraint that had been forced on Carnage from his host. This left Spider-Girl in a difficult position as she tried not to hurt her brother. Recalling that symbiotes were vulnerable to fire and sonics, she asked her dad to bring in some sonic weaponry to try and save Benjy. It was a gamble, one that paid off with a terrible cost. Benjy was freed from the symbiote, but lost his hearing.
Although Benjy would later regain his hearing thanks to an expensive operation, this event highlights how the symbiotes have the tendency to become generational problems. Their very nature means that they also spawn new symbiotes and they usually stick close to their former hosts. In the main Marvel Universe, no one better exemplifies the struggle this brings than Dylan Brock, the son of Eddie. His latent connection to the symbiotes not only made him a powerful force, but also a victim for their god Knull.
Dylan suffered at the hands of the King in Black, tormented and manipulated in a bid to remove any potential threats to Knull's plans of universal conquest. Fortunately, things turned out okay for Dylan, but Benjy's encounter with Carnage demonstrated that these victories often come at the cost of lasting physical damage or emotional and mental turmoil. Dylan had difficulties letting go of the anger that lingered inside him, Benjy suffered a debilitating injury to be freed of Carnage, and his sister was left guilt-ridden by the extremes she went through to free her brother.