For example a flame who looks like a flame
Or a typography snow who looks like snow
Do you know the name of this exercice ?
The term for words of this nature are "autological" (e.g. "short" is autological because it is short; "long" is not because it is a short word).
This has been extended to the visual medium(s) via the word "autologlyph"
In literature, it's called "onomatopoeia," so I'd coin "fontomatopoeia."
I know it as Expressive Typography
While Lauren's answer is certainly the best. Often this style of typography is referred to as "display type". Other than that, I don't think there's a specific name.
It's not in any way skeuomorphic. This term has to be the most mis0used term on the interwebs this decade. I'd agree it's almost hyperreal which people often should be saying when they say skeuomorphic.
They're almost ideograms. However ideograms are wordless images, which of themselves form words in some written languages (East Asian, Ancient Egyptian languages) (paradox is only apparent I'm just not saying it correctly!)
it's often referred to as "ornamental"