That was pretty brazen alright. :)

Yep. Those ads were so effective that, to this day, I kind of hate Sonic/Sega, lol.

Did Nintendo ever attack competitors in their ads?

I remember a very civilized Nintendo print ad in the 16 bit era that went after Sega for releasing so many add-ons. I think it may have even mentioned the Saturn ( although not by name ). It was pretty dry, and read more like a PSA than a video game ad, but it liked it at the time, and thought it made some good points. This was right before Nintendo changed things up to counter Sega, and launched their "Play It Loud" campaign, which was heavy on elements such as: Skateboards flying through the air, young people screaming, and old people being stupid.

Yeah, imagine if that happened today, like if MS made an add-on that allowed you to play PS4 games.

probably this : https://www.youtube.com/watch?v=kWSIFh8ICaA

When MS was being really anti consumer, with:
always online, DRM, game buy = license used up when installed, shareing games would  cost you money ect ect.

Sony put out this "here's who you trade a PS4 game" video and it musta felt like a kick to the nuts for Xbox.

Indeed. It's a crazy idea that would never happen again. Quite sure there was a lawsuit against Coleco over the adapter, but I'm too lazy to look it up. The closest thing to this was the Bleemcast!, an adapter that allowed Dreamcast users to play PS1 games on the Dreamcast. It ( obviously ) wasn't an official Sega product, but it was fairly mainstream, and marketed quite often in gaming magazines. Again, can't remember the legal outcome, but Sony was aggressive in trying to have it removed from the market.

Bleemcast was actually deemed legal, but the court costs essentially killed them anyway.

Ah! OK. Thanks for the info.

Here's a good documentary on it: