Need to know what song this is....

Ok, I was listening to the radio the other day and they had a old school hip hop/rap lunch hour.They didnt say who the artist was or the song but here is what I picked up from the lyrics-
"Grim reaper"
"Charlie Brown"
"Teacher, wa wa wa.."
I've tried many times to google search and found nothing. I also searched on lyrics sites.
If anyone knows who the artist is and the song title please let me know.I greatly appreciate it! Thank you