“What do you call a frog spy?”/“A croak and dagger agent.”

A frog riddle is:
 
Q: What do you call a frog spy?
A: A croak and dagger agent.
 
The joke has been cited in print since at least 1978.
 
     
Wikipedia: Cloak and dagger
“Cloak and dagger” refers to situations involving intrigue, secrecy, espionage, or mystery.
   
Google Books
The Crack-a-Joke Book
Harmondsworth, UK: Penguin Books
1978
Pg. 155:
What do you call a frog spy ?
A croak and dagger agent.
       
23 June 2005, North Island Gazette (Alert Bay, BC), “Solve the mystery of kids’ summer boredom at library,” pg. 11:
What do you call a frog spy?
A croak and dagger agent!
   
Twitter
Bollywood Sargam
@bollywoodsargam
Frog jokes - 5130 Joke: What do you call a frog spy ? A croak and dagger agent ! .... http://htxt.it/KjaO
7:49 PM - 2 Jul 2009
 
Google Books
The Mammoth Book of Really Silly Jokes:
Humour for the whole family
Edited by Geoff Tibballs
London, UK: Constable & Robinson Ltd
2011
Pg. ?
What do you calla frog spy?
A croak and dagger agent.
     
Google Books
Sensible Nonsense.. Frank’s Comic Pack:
Humour Pack Series
By Frank Paul
BookBaby
2014
Pg. ?:
What do you call a frog spy ? A croak and dagger agent
 
Twitter
Lucky Score
@LuckyScoreNet
What do you call a frog spy ?
A croak and
dagger agent !
#Joke from #FrogJokes in #Jokes, #Humor and #Satire
1:27 AM - 19 Mar 2018