The N64 Game Boy Pak, an adapter for the Nintendo 64 video game console.  The Game Boy Pak allowed you to connect Game Boy games to the N64 through the controller, which was only used for a few games.
<a href="//commons.wikimedia.org/wiki/User:Evan-Amos" title="User:Evan-Amos">Evan-Amos</a>
<span class="int-own-work" lang="en">Own work</span>