dematerialize or dematerialise  (ˌdiːməˈtɪərɪəˌlaɪz)

1. To cease to have material existence, as in science fiction or spiritualism
2. To disappear without trace; vanish

↓ Transcript

[ Panel 1 ]
GENTLEMAN 1: Sir, WHAT is happening to you?
GENTLEMAN 2: I haven’t had sexual relations in a year. I fear I am fading away like no one cares!
:: The second gentleman is at 50 opacity of a normal human being, he’s almost a ghost. Gentleman 1 is fully corporeal. ::

[ Panel 2 ]
GENTLEMAN 1: Psh! It’s been over two years for me!
GENTLEMAN 2: …and how does that make you feel?

[ Panel 3 ]
:: The first gentleman immediately begins to fade away, ever more than gentleman 2. At this point almost to nothing, in moments. ::