Since I posted a Nintendo disaster a few days ago, I figured it's only fair to post a Sega (NES's biggest rival back in the day) disaster as well. So far, I haven't found a Sega commercial produced directly by Sega themselves. But I did find this Toys R Us disaster prominently featuring the Sega Master System.
Toys R Us's mascot, Geoffrey Giraffe, has definitely seen better days. Not only is Geoffrey as lifeless as Melanie Griffith's career, but he also boasts of the unlimited game power of... wait for it... 256k! That may have been a huge amount for a game back then, but there's no way that was ever considered "unlimited"!