Chris Rosa

"Only Ms. Rosa's boy, running around in his Halloween costume, more than a week early. I swear, the nerve of that woman leaving her brat unsupervised."

- Codsworth

Ms. Rosa's son is a Feral ghoul living in the Commonwealth in 2287. He is encountered in a random encounter post-War, being one of a group of hostile ghouls.

Background
Before the war, Ms. Rosa's son was presumably one of the neighbors of the Sole Survivor who was restoring an old Corvega with his mother. When the bombs fell, they didn't make it to safety. He can be found 210 years later roaming the Commonwealth and Boston with Rosa and a few other unlucky pre-War citizens turned ghoul.

After the nukes fell, Codsworth tells the protagonist that he had seen "Ms. Rosa's boy running around in his Halloween costume," implying that Codsworth had seen him as a ghoul and mistaken his ghastly appearance as simply a costume.

Appearances
Ms. Rosa's son appears only in Fallout 4.