“How do you make an elephant float?”/“Just add ice cream.”

An elephant riddle is:
 
Q: How do you make an elephant float?
A: With two scoops of ice cream, and elephant and some root beer.
 
The elephant joke became very popular in 1963.
 
“How can you make a turkey float?”/“Get 2 ice cream scoops, root beer and a turkey” is a similar riddle from 2000.
 
   
Wikipedia: Ice cream float
An ice cream float or soda (United States, United Kingdom, Canada, South Africa and East Asia), coke float (United Kingdom), root beer float (United States, Canada) or spider (Australia and New Zealand), is a beverage that consists of ice cream in either a soft drink or in a mixture of flavored syrup and carbonated water.
     
6 June 1963, Minneapolis (MN) Morning Tribune, “After Last Night” by Will Jones, pg. 42, col. 7:
Q. How do you make an elephant float?
A. With two scoops of ice cream, an elephant and some root beer.
 
6 July 1963, Detroit (MI) Free Press,“The Town Crier” by Mark Beltaire, pg. 8-C, col. 3:
Joyce Braithwaite of Charlotte wonders if you know how to make an elephant float. Just pour root beer, add two scoops of ice cream and an elephant.
 
16 August 1963, Newsday (Long Island, NY), “It Happened Last Night” by Earl Wilson, pg. 7C, col. 2:
“How do you make an elephant float?”....“Easy. Two scoops of ice cream, an elephant, and root beer.”
   
Google Books
Time magazine
1963
Pg. 41:
Everyone has a trunkful of his own. Among the woollier samples:
 
Q. How do you make an elephant float? A. With two scoops of ice cream, an elephant and some root beer.
 
Google Books
December 1963, Boys’ Life, “Think and Grin,” pg.96, col. 4:
Pete: Do you know how to make an elephant float?
Repete: No, how?
Pete: Mix ice cream, root beer and one elephant. — George Sims, Jr., Chicago 52, III.
   
OCLC WorldCat record
How do you make an elephant float? and other delicious riddles
Author: Lee Bennett Hopkins; Rosekrans Hoffman
Publisher: Niles, Ill. : A. Whitman, ©1983.
Edition/Format:   Print book : Juvenile audience : English
   
Google Books
Get Thee to a Punnery:
An Anthology of Intentional Assaults Upon the English Language
By Richard Lederer
Layton, UT: Gibbs Smith
2006
Pg. ?:
How do you make an elephant float?
Use a scoop of ice cream, some root beer, and an elephant.
 
Twitter
Jasini‏
@Jasini
How do you make an elephant float?  Just add ice cream.
1:47 PM - 23 Aug 2008
 
Reddit—Jokes
How do you make an elephant float?
submitted September 3, 2014 by PannacottaArmy
A can of coke, a scoop of vanilla ice cream, and an elephant.
 
Reddit—Jokes
Wanna know how you can make an elephant float?
submitted July 9, 2017 by ImHereForTheMedals
One elephant, two scoops of ice cream.