The Crier for Mick and Ralph is an NPC found in the base game of Fallout: New Vegas. He resides in Freeside, standing outside the gate that leads to the inner part of the slum. He advertises the store Mick and Ralph's, a guns and general store in the area.
The crier is a particularly annoying NPC in Al's mind. It's worth mentioning however, that even Josh Sawyer himself, the Project Director for Fallout: New Vegas, admitted to regretting implementing the Crier, believing him to be too annoying and a poor design decision, given that it drives players to want to shoot him only to have their immersion shattered when they realize they can't because he's a child, so Al's annoyance with the Crier is well understood.
As with all NPC's that make a habit of talking, let alone shouting, Al hates the Crier. In various videos, he is attacked and killed by Al, using the Childkiller mod (in Fallout: New Vegas, children cannot be killed without the use of a mod).