In the pages of Shazam! #2 (published February 15, 1973) we are introduced to a new character in Captain Marvel's comics. In the story, "The Nicest Guy in the World" Sunny Sparkle makes his first appearance and we learn that Sunny has a unique problem that turns out to help Cap solve a crime!
We first meet Sunny Sparkle as he attempts to sneak past a crowd. Why is Sunny sneaking about? Because people just can't resist doing nice things for Sunny! People give him books, coats, food - they want to do something nice for him. This unique problem turns into a bigger problem when two bank robbers pass by Sunny and they feel so compelled to do something nice for him - they give him all the money they just stole! Prior to meeting up with Sunny, the two thieves socked Billy Batson and made a getaway from Captain Marvel with a smoke machine built into their car.
Meanwhile, the two bank robbers report back to their boss who is infuriated that they gave away the loot. The boss tucks a pistol into his coat pocket and tells his crew, "I'll get him!" The boss shows up at Sunny's house, reaches into his coat pocket and lets Sunny have it - more money that is! Back at the hide-out the boss laments that he can't handle Sunny. But one of his thugs hatches a plan to get back their stolen money.
The boss runs across Billy Batson and asks Billy if he knows Sunny. Billy says he does, and the boss tells him that Sunny was to give him some money for charity and asks Billy if he can get it for him. Billy goes to Sunny's home, and with his mom's permission, retrieves the satchel full of loot. The crooks take off but Billy recognizes them as the bank robbers because of the smoke coming from their car.
Billy says the magic word, "Shazam!" and transforms into Captain Marvel who quickly captures the trio of crooks. The next day, Sunny Sparkle is in the Mayor's office along with Captain Marvel and is presented a medal for his assistance in helping Cap catch the crooks. But the Mayor and others can't resist giving Sunny even more things because he is the nicest guy in the world!