The robot administers a small pin prick at random to certain people of its choosing.
The tiny injury pierces the flesh and draws blood.
Mr Reben has nicknamed it ‘The First Law’ after a set of rules devised by sci-fi author Isaac Asimov.
He created it to generate discussion around our fear of man made machines. He says his latest device shows we need to prepare for the worst
‘Obviously, a needle is a minimum amount of injury, however – now that this class of robot exists, it will have to be confronted,’ Mr Reben said on his website.
Here is more, with pictures of (slightly) injured humans, via the excellent Mark Thorson.