Synonyms for Scrunch (same or very similar meaning)
WordNet sense 1 (make a noise typical of an engine lacking lubricants):
thud, crumpWordNet sense 2 (sit on one's heels):
crouch, hunker, squat, hunker down, scrunch upWordNet sense 3 (make wrinkles or creases into a smooth surface):
crease, crinkle, crisp, wrinkle, ruckleFrom the ODE community, based on WordNetadd/edit