“Did you hear about the ghost comedian? He was booed off stage” is a popular ghost pun. The joke has been cited in print since at least 2003.
 
   
25 October 2003, Evening Mail (Birmingham, UK), “Chipper Club: Spooky Jokes,” pg. 42:   
Did you hear about the ghost comedian? He was boo-ed off stage!
 
Twitter
Bollywood Sargam
@bollywoodsargam
Ghost jokes - 5157 Joke: Did you hear about the ghost comedian? He was booed off stage. .... http://bit.ly/gv3l6
3:26 AM - 24 Sep 2009
     
Google Books
Sensible Nonsense.. Frank’s Comic Pack:
Humour Pack Series, Volume 1
By Frank Paul
BookBaby
2014
Pg. ?:
Did you hear about the ghost comedian? He was booed off stage.
       
7 March 2014, Fraser Coast Chronicle (Maryborough, Queensland), “Joke of the Day,” pg. 12:
Did you hear about the ghost comedian?
He was booed off stage.
 
Google Books
Dad Jokes:
Good, Clean Fun for All Ages!
By Jimmy Niro
Naperville, IL: Sourcebooks, Inc.
2018
Pg. ?:
Did you hear about the ghost comedian? He was booed off stage.
 
Twitter
Lorraine Jo King
@lahlahbean
#badjokethursday
Did you hear about the ghost comedian?
He was booed off stage.
2:10 AM - 30 May 2019