Warning! SPOILERS for The Black Phone.
A small detail in The Black Phone draws an important parallel between The Grabber and another character that cements the importance of the film's darkest theme. Adapted from Joe Hill's short story of the same name, The Black Phone primarily concerns Finney Blake, a boy taken by a serial child abductor and murderer known as The Grabber (Ethan Hawke). The Black Phone draws on elements of the supernatural, as well as more realistic horror, making for an unforgettably chilling watch.
One element of The Black Phone that stands out is its stark exploration of the theme of child abuse and the emotional and psychological effect it can have on victims. This is most obvious in The Grabber's treatment of his victims, but Finney and his sister, Gwen, are also subjected to abuse at home from their father, Terrence. Terrence is shown to be an alcoholic who subjects both of his children to physical and emotional abuse, directing tirades at them for the most mundane reasons and imagined transgressions.
The most obvious characteristic of The Grabber is his mask, which changes from scene to scene to reflect his mood and his plans. The Grabber's mask in The Black Phone is used as a way of allowing the character to hide from himself and his victims, but it also draws a visual parallel with Finney and Gwen's father. Terrence's most obvious physical feature is his large beard, which obscures his face in a manner not dissimilar to The Grabber's mask. That The Black Phone shows the two most abusive figures in Finney's life both having faces obscured helps create a subtle narrative link between the abuse Finn suffers at home and the torment of The Grabber.
The similarities between The Grabber and Terrence Blake are small but significant. The beard/mask connection is the most obvious, but there are also scenes with each man asleep in a chair, and Finney attempting not to wake them. In these small ways, The Grabber in The Black Phone and Finney's father play similar roles in the boy's life - he is stuck with their controlling and abusive natures and initially unwilling to fight back. The implication of Finn killing and escaping The Grabber is that he has found the strength to stand up for himself, and his father's remorse offers him some mild redemption in the film's final scenes.
The visual parallels between Terrence and The Grabber are important, as they offset the father's ending. Though Terrence may be sorry, the ways that he and The Grabber are alike make it clear to the audience that he deserves no sympathy. Like The Grabber, Terrence Blake is yet another tormentor in Finney's life, and he contributes to the cycle of abuse that Finney is forced to escape in The Black Phone.