As far as I know, the N64 was the first console to have it’s own mouse. That in itself is quite an achievement, however what is even cooler is that the mouse wasn’t complete trash – it was actually quite useful apparently.
Unfortunately it was only ever available in Japan, and was designed to work alongside the 64DD (another cool accessory). They’re also pretty hard to get a hold of, I found only a few online and they seemed to be pretty expensive (plus I don’t have a 64DD). The mouse came bundled with an N64DD game, Mario Artist: Paint Studio.
The mouse made it much easier for gamers to apply the elegant touches needed to play MA:PS, so it was definitely a useful accessory.
If you want a laugh, there is a very funny video of a guy beating Mario 64 only using a mouse, check it out here.