The flashback sequences address Charles' early childhood friendship with a young Eddie Caputo. Eddie is the second person Chucky kills in the original feature.
As the detective collected Chucky, he remarked that he was "a f***ing ugly doll." Chucky was similarly insulted by an elderly lady in the original Child's Play. Where she only received a verbal rebuttal, the officer met a much more brutal fate.
Chucky own climactic moment saw the killer doll give Jake, Lexy, and Devon his middle finger. The move has long been a staple of Chucky's, offered up to several enemies over the decades. Last delivered to Nica in Cult of Chucky, it now solidified the end of his and Jake's friendship. Equally, it marked Jake, Lexy, and Devon as the official heroes of Chucky as they unite to stop him.
Chucky offered this sardonic one-liner before stabbing the aforementioned detective with a dagger of needles. This was paraphrased from Cult of Chucky (2017), which saw him equally terrorize a medical facility. The tagline for that sequel read: "You may feel a little prick."
During Chucky episode 4's flashbacks, the teenage Charles could be seen reading and playing twisted games based on Peter Pan. As well as informing why Chucky wants to remain a doll, it also explained elements of his wider M.O., especially regarding child proteges.