#12 - Bushes and Clouds

At this point, it should be no mystery that the bushes and the clouds in Super Mario Bros. are just palette swaps of each other. However, this happens again in Mario Kart 7, as in Piranha Plant Pipeway, bushes and clouds use the same art, but recoloured.

SOURCE: https://www.neogaf.com/threads/videogame-facts-that-blow-your-mind-supermariobros-shocking-secret-inside-p-70.232550/page-192