While Jim Carrey's character, Chip Douglas, doesn't actually try to kill the kids, he does become increasingly obsessive and dangerous, leading to a chaotic and ultimately threatening situation for the children and their foster family.
It's important to note that "The Cable Guy" is a dark comedy, and the events depicted are meant to be exaggerated and comedic. However, the film does explore themes of obsession, manipulation, and the dark side of human nature.