The process of metamorphism (or the process that makes existing rocks into metamorphic rocks) does not melt the rocks, but rather transforms them into denser, more compact rocks through either rearrangement of mineral components or reactions with fluids that enter the rocks during the transformation process. The rocks are typically squished, smeared out, and folded, but they do not get hot enough to melt — if they did, they would be classified as igneous rocks instead.