Oh those crazy scientists with their buttons, dials and knobs. Also did he just negate the threat to his new movie? Watch the entire interview at the Daily Show.
Create a macroscopic quantity of antimatter— say, a chunk that would fit handily into the space between Hanks' finger and thumb when he mimes the answer to "How much did you have?"— and there'd be a pretty severe explosion hazard. But of course, we don't have the facilities to do that, let alone the energy it'd require (at current efficiencies.) According to Wikipedia,
if everything goes well with ATHENA, it might be possible to bring production up to a hundred antihydrogen atoms per second.
Turn off the equipment, and the stuff bonks into conventional matter, undergoes mutual annihilation, and disappears in a blaze of neutrinos and gamma. Total energy liberated is about 3.01 x 10^-10 Joules per atom of antihydrogen involved.