TIL the Gameboy had a sonar add-on for fishermen, that could

Game Boy Accessories

The Pocket Sonar Was A Strange Game Boy Accessory That Helped You Fish

A Look At The Game Boy Fishing Accessory – NintendoSoup

Game Boy / Platform - TV Tropes

10 Weirdest Portable Video Game Accesories Ever Made

The Best Weird Nintendo Experiences - GameSpot

Is The Gameboy Dead: [A Complete Guide To Gameboys]

The Official Game Boy Thread - Page 7 - Classic Console Discussion - AtariAge Forums

Nerdly Pleasures: The Everdrive GB Review - Game Boy and Game Boy Color Fans Rejoice : Your Prayers Have Been Answered!