Well, I mean from electrocution specifically. 100-200mA through your heart is probably going to be fatal, and the low resistance required for that to happen wit

Well, I mean from electrocution specifically. 100-200mA through your heart is probably going to be fatal, and the low resistance required for that to happen with a simple 9V battery source has at least once been achieved by inserting multimeter probes in the thumbs such that the current passed via the blood stream through the heart, causing fibrillation. Interestingly, there exists a sort of upper threshold where the amperage is less likely to be fatal due to severe cramps preventing fibrillation IIRC.