Marvel Boy, Vol. 2

A Kree vessel capable of traveling across realities passes near a version of earth and is shot down, with only one survivor. The survivor is taken captive, where he is to be tortured and vivisected for research. His only response to his captors is to sneer or spit. He's hard to break, as he can route pain impulses to his auditory cortex, meaning attempts to hurt him seem to him as though music is playing. His spit contains nanotechnology, so he makes an escape by spitting on an insufficiently protected guard whom he then controls. He ends by deciding to fix this Earth in his own way.