I do think that that should be quite painful. 9v may not seem like much but on broken skin if contact is good you will feel it quite right. Also Clark zappers operate by battery and provide a pulsed dc voltage. Positive at one hand hold negative at the other. If you had both contacts connected and one side had a switch going to one of the terminals of the battery and you could turn it on 15000 times a sec that gives you a basic of operation.