I've long known 冷やす as the transitive counterpart of 冷える. But thanks to one question here, I've realized that there is another version with an extra syllable in it: 冷やかす. Although 冷やかす seems to have secondary meaning of making fun of someone, the first meaning "to refrigerate" seems to overlap with 冷やす. Is there any difference between them?
Being curious, I looked up in the dictionary for other verbs that have "Xsu" and "Xkasu" variants and found another pair: 散らかす and 散らす. Same question, how are they different?
Lastly, are there any other verb pairs that are different in look from each other by one additional syllable while still maintaining transitivity, and would there be any pattern on how the verbs in each pair different from each other?