You can't. Note the fact that when ground-pounded, Boo says "Ghosts... Don't... Die!"
You ground pound it, or run around it and punch it.
you cant Yoshi cant kill ghosts
You cannot really kill ghosts in Super Mario unless you have an invincibility star in use. However, you can stop them by looking at them, which makes them cover their faces.
you cant
No.
you defeat all of the boos (ghosts) and the star will appear
You run around it.
Ghosts are definitely scared of lights. Yes, lights can really kill ghosts.
kill i think 8 boos
Thirteen Ghosts.
what one Mario 64 ds or Mario 64 nes
Ghosts can't eat or kill you but they can hurt you. No they aren't werid.