Hi Diddle Riddle

Main Characters

 * Dynamic Duo (first appearance)
 * Batman (Bruce Wayne) (first appearance)
 * Robin (Richard Grayson) (first appearance)
 * Alfred Pennyworth (first appearance)
 * Gotham City Police Department (first appearance)
 * Commissioner James Gordon (first appearance)
 * Chief Miles O'Hara (first appearance)
 * Harriet Cooper (first appearance)

Villains

 * Mole Hill Mob (first appearance)
 * The Riddler (first appearance)
 * Harry (first appearance)
 * Molly (first appearance)

Other Characters

 * Bruce Wayne's Father (first appearance; mentioned)
 * Bruce Wayne's Mother (first appearance; mentioned)
 * Gideon Peale (first appearance)
 * Inspector Basch (first appearance)
 * Moldavian Prime Minister (first appearance)
 * Mr. Harris (first appearance)

Teams and Organizations

 * Gideon Peale Co. (first appearance)
 * Gotham City Police Department (first appearance)
 * Mole Hill Mob (first appearance)
 * What a Way to Go-Go (first appearance)

Species

 * Humans (first appearance)

Objects

 * Bat-Belt (first appearance)
 * Bat-a-Rang (first appearance)
 * Bat-Cuffs (first appearance)
 * Bat-Hook (first appearance)
 * Laser Gun (first appearance)
 * Smoke Pellets (first appearance)
 * Bat-Computer (first appearance)
 * Bat-Phone (first appearance)
 * Batmobile (first appearance)
 * Batpoles (first appearance)
 * Bat Signal (first appearance)
 * Batsuit (first appearance)
 * Lighter Gun (first appearance)
 * Robin Suit (first appearance)
 * The Riddler's Cane (first appearance)
 * The Riddler's Dart Gun (first appearance)
 * The Riddler Suits (first appearance)
 * William Shakespeare Bust (first appearance)

Locations

 * Earth-66 (first appearance)
 * Earth (first appearance)
 * Republic of Moldavia (first appearance; mentioned)
 * United States of America (first appearance)
 * Gotham City (first appearance)
 * Gotham City Hall (first appearance)
 * Gotham City Police Headquarters (first appearance)
 * Gotham City World's Fair (first appearance)
 * Republic of Moldavia Pavilion (first appearance)
 * Mole Hill Mob Headquarters (first appearance)
 * Peale Art Gallery (first appearance)
 * Gideon Peale's Office (first appearance)
 * What a Way to Go-Go (first appearance)
 * Wayne Manor (first appearance)
 * Batcave (first appearance)

Trivia

 * The opening footage of the Gotham City World's Fair is stock footage from the 1964/65 New York World's Fair.
 * After the Moldavian Prime Minister cuts into the Friendship Cake, he yells expletives in German rather than the native language of his county, Romanian.
 * This episode features the first appearance of the Batusi dance.