Dumbest looking "fighting game" on the system is clearly Dragonball GT: Final Bout. When I first saw it at a Toys R Us for $10 as a kid I was super excited. Anime wasn't as common of a thing back then and this was a bit before the show had exploded in the states so DB was a mostly unknown property at the time. Anyway, the store had 2 copies so my friend and I bought them both. I took it home, booted it up, saw the Sweet intro FMV, and was on the moon. Then the game started. Man, that shit was Terrible! I played it a few times, put it on the shelf, barely ever thought of it again. I played it with friends a few times because they saw it, a Dragonball game, and didn't believe me that it was so terrible.
Five years or so later I was doing some dumb searching on games and came upon an unusual surprise: that trash game that I had I purchased for $10 was suddenly worth $450. When I went home for Christmas break I sold my copy on ebay and made a grip of money. I told my friend who had purchased his copy at the same time and he said he was going to do the same. He looked and looked but couldn't find it. In the end he asked his little brother and found out that his game had been sold for $50 to a kid down the street.