Having recently trodden on a disembowelled "small furry creature" I would not bank on that Hairy little toerag, Wugsie, not knowing what to do with it and possibly viewing it as a tasty snackette and diet supplement,
I hate to suggest the obvious, but the waste bin outside the kitchen door has the remains of some cat food tins in it, could this be the "source" of the offensive odour? AFAIK there are No fugitive socks!