Presume he had just ate a power pellet, of course.
Followup matchups for your consideration:
- Slimer, from “Ghostbusters”
- Sadako, from “The Ring”
- Freddy Krueger, from “Nightmare on Elm Street”
- The clown from “It”
- A ring wraith from “Lord of the Rings”
The power pellets only affect ghosts after said pellets are eaten by Pac-Man, as the ghosts can float over pellets without issue. Thus I think its a safe assumption that making the ghosts material form edible one time, temporarily is a result of Pac-Man’s magnified power rather then the pellet itself.
Hence the question.