The term 'start to morph' is a phrase that refers to the process of transformation. In this context, the crossword solutions ENDO and ECTO refer to two different types of morphs. ENDO is short for endomorph, which is a type of body shape characterized by having a rounder body type with more fat and muscle mass. ECTO is short for ectomorph, which is a type of body shape characterized by having a leaner body type with less fat and muscle mass. Together, these two terms represent the two extremes of body types and the process of transformation between them.