It might be just good old body capacitance?
"Transient electromagnetic noise generated by ESD (ElectroStatic Discharge) is considered to cause serious electromagnetic interference to high-tech devices. One of the main causes of this ESD is known to be charging of the human body. Hence, the static capacitance of the human body, which is deeply related to the human body potential, has been measured. However, the body capacitance is strongly dependent on the relationship between the ground plane and the body posture. It is therefore not clear what factors govern the body capacitance. In this paper, the static capacitance of a body standing on a ground plane is calculated by means of the surface charge method. The human body consists of polyhedra in the calculation. In this paper, three types of polyhedra, with 765, 917, and 1529 surfaces, are used. It is found that the capacitance increases as the backs of the soles of the shoes approach the ground plane, that the body capacitance at the same height (10 mm) as the soles of the shoes is 120 to 130 pF, and that it is about 60 pF if the location of the soles is sufficiently high. The computational findings are confirmed by measurement of the body capacitance."
I knew all that off by heart but couldn't be bothered to put it n my own words so I did a lazy arse cut & paste