Sentence: He in his turn was succeeded by a fat, fussy little person, who literally threw himself into my arms he held his goldlaced hat in one hand, while with the other he wiped the perspiration from his forehead he stammered an apology, and then rolled off again like a ball down the hill.
Combination: a ball down the hill (root: ball, modifier: hill)
Property: unstoppable
Property type: emergent