The expression "walking skeleton" as in: "Little more than a walking skeleton after weeks on the run..." (https://en.wikipedia.org/wiki/Dieter_Dengler#Rescue).
One could say, „marŝanta skeleto” (similar to 'marŝanta mortinto') but it sounds like an anglicism.
Or „vojaĝanta skeleto” from the French, « squelette ambulant », but yet again, this one sounds like a gallicism.
Or even „skeletulo” (https://www.wikiwand.com/eo/Mortulo) but this seems to apply to a fantasy-like dead being. Or „vivanta skeleto”.
Is there an commonly use expression?