Also from the article, this seems a lot more plausible:

The flatlands of Carmen were once a playground for giant children. One day, they initiated a contest on who could bake the most mud cakes, gathering mud and “baking” them under coconut half-shells laid flat on the ground. Before the contest could end, however, the children were called home. After a while, they returned to the area to witness their finished creations and left them undisturbed out of admiration—the baked cakes thus became the hills.