Right, slightly unfeasible, but technically possible.
Lead box with sides a few miles thick, and set off a few nukes inside him with it in it, one after the other. Have the inside of the box just big enough for him and the nukes. Should work.
Lead box with sides a few miles thick, and set off a few nukes inside him with it in it, one after the other. Have the inside of the box just big enough for him and the nukes. Should work.