Oh yeah. They used it so little that it got intelligence cancer and the 'doc had to remove it with a shovel. To avoid getting a disease from the somewhat large cut on his head, he was given a treatment... the stupidity syringe. It would make sure that no intelligence leaked through his skin ever again. Since the Intelligence cancer got into his DNA, the cancer would spread into any new intelligence.
Or we could lower everything he cares about into a grinder and make him watch. Then we'll cut off his arms, legs, and tongue and throw him into the ocean. He won't be able to swim, and sharks will be attracted. If he somehow doesn't die from those two things, he'll just die of blood loss. If he is immortal, he'll be lying at the bottom of the ocean until the end of the world. Then he'll be floating in space, feeling the pain of the vacuums trying to pull apart his body forever.