LogFAQs > #974399955

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Every other aspect of the first Super Mario Bros. game became a mainstay for the series. The Goombas, Koopas, Lakitus, etc. The Japanese version of Super Mario Bros. 2, which was honestly little more than an expansion pack for the first game, was the only other title in the series to feature a firebar until Yoshi's Island a decade later. They've since appeared in Paper Mario, New Super Mario Bros., and a couple of others. But when it came to the retro era of Mario, it's the only hazard that that remained exclusive to the first game.

And it didn't start out as a Mario hazard either. It was originally meant to be in The Legend of Zelda before the programmers decided that it was more appropriate for Mario.