“What did the ghost teacher say to her class?”/“Watch the board and I’ll go through it again!”

A popular Halloween riddle about a ghost teacher is:
 
Q: What did the ghost teacher say to her class?
A: “Watch the board and I’ll go through it again!”
 
The riddle has been cited in print since at least 2003 (in a slightly different form) and 2006.
 
 
Google Groups: alt.sports.soccer.everton
Whoooooooooooo!
Quaggers
10/13/03
The teacher at the ghost academy was teaching his pupils how to pass right through a wall.
“Now did you all follow that?” asked the teacher.
“If not…..............I’ll just go through it again!”
 
Google Groups: The Hallowe’en Party
Halloween Jokes
.(JavaScript must be enabled to view this email address)
9/18/06
A ghost joke
What did the ghost teacher say to her class?
Watch the board and I’ll go through it again!
 
Twitter
Rob Lawrence
‏@keepasecret
What did the ghost teacher say to her class?  Watch the board and I ‘ll go through it again!  http://www.themidnightreport.com  😊
9:31 AM - 30 Mar 2009
 
Google Books
The Mammoth Book of Really Silly Jokes
By Geoff Tibballs
London: Constable & Robinson, Ltd
2011
Pg. 133:
What did the ghost teacher say to her class?
Watch the board and I’ll go through it again.
 
Google Books
Insults Anywhere Kids Presents
Joke Book Of The Living Dead
By Franklin Yantz
Published by Insults Anywhere at Smashwords
2011
Pg. ?:
What did the ghost teacher say to her class?
Watch the board and I’ll go through it again!
 
Google Books
101 Amazing Spooky Jokes
By Jack Goldstein
Andrews UK Limited
2013
Pg. ?:
What did the ghost teacher say to her class?
Watch the board and I’ll go through it again!
 
Twitter
Christian Fletcher
‏@Darth_Pingu
#HappyPunoween
Q: What did the ghost teacher say to their students?
A: “Watch the board, I’ll go through it again!”
4:31 PM - 29 Oct 2016