Wasabi is a plant in the same family, but most commercial wasabi is just horseradish with green food coloring. In the word “horseradish,” “horse” means strong or coarse. Horseradish in general isn’t hot unless cut or grated, when enzymes digest sinigrin to produce a sharp-tasting essential oil. This oil is a defense against bugs and herbivores, but has had the paradoxical effect of attracting us.