I really want to do this kind of effect where it looks like a person is disintegrating away, but I have no idea what it is called:
THanks To Bala's clue in the comment.... I found the original source photo....
It's merely Adobe Photoshop's Oil Paint Filter
Here's one with these settings:
This is a completely new image generated by running the oil paint filter on the same source photo. This is not merely a reposting of your sample image.
The Oil Paint filter mentioned in Scott's answer was removed from Photoshop in version CC-2014. For those using Windows, Adobe has recommended using the GREYCstoration plugin:
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