Seashore City has 3 unused NPCs tucked in the corner of the map
The Old Man Glitch is a glitch found in across the 1st Generation Pokémon games, this includes all hacks under the same engine who did not go out of their way to fix it, including Pokémon Brown.
Explanation and Methods[]
Please refer to the Bulbapedia article for detailed info.
Old Man Glitch in Pokémon Brown[]
While the glitch is present within Pokémon Brown, it cannot be activated through normal means and requires prior setup and usage of a walk-through-walls glitch. The Old Man still exists in the game but was moved out of bounds in the southeast corner of Seashore City, while a functionally identical seashore to the Cinnabar Island one is only found out of bounds south of Owsauri City[Route 66?].