Creation and development in Thimble Theatre
Six months prior to their encounter with Popeye and Swee'Pea, Snagg and Baby Doll were notorious thieves in Spinachovia who made off with the map leading to the location of the country's royal jewels. Wrought with worry, King Blozo requested the help of the head of the Spinachovian Secret Service, Mervin M. Mouser, to retrieve the map and arrest the scoundrels.
After their successful theft of the royal map, Snagg and Baby Doll left Spinachovia and made their way overseas to a small port town to hide out in until the heat died down. To make sure they would not be caught with the stolen map, they decided to hide it away somewhere no one would ever look. That is when they concocted a most devious plan; they proceeded to kidnap a small child via hypnosis and, while the child was knocked out, Snagg copied the map onto the child's back using indelible invisible ink so it would remain undetected by the child's guardian, and then proceeded to destroy the original map. After successfully acquiring the child for the scheme and carrying out the deed, they returned the child before he awoke as to avoid anyone knowing of what they had done. They then hid away for six months until they knew it was safe to retrieve their map. However, the child in question turned out to be none other than Swee'Pea.
Several months had passed since the crooks disappeared, only to return prowling the yard behind by Popeye's home, sinisterly eyeing the oblivious Swee'Pea and waiting for a chance to kidnap him once again while remaining undetected. When the chance presented itself, they immediately tried to abduct the "boy-kid", but their evil attempt was thwarted by Swee'Pea's cries as they were heard by his beloved father figure, Popeye, who made short work of the two crooks. Returning to their hideout, the duo realized that they had picked the worst child for their scheme, as even they knew of Popeye's prowess. Yet Snagg was not quick to give up and promptly concocted a new plan, this time disguising himself as a book salesman in order to lower Popeye's guard long enough to run off with the child. The plan briefly worked as Snagg escaped with Swee'Pea hidden in his suitcase, but unbeknownst to him and Baby Doll, Swee'Pea was able to break free from the broken rear of the suitcase without them knowing.
By the time Swee'Pea returned home, Popeye was growing concerned over the would-be kidnappers, wondering what they were after in Swee'Pea, but just then, a large package arrived and inside was Mervin M. Mouser of the Spinachovian Secret Service, who wished to speak with Popeye in hopes of informing him what transpired in the kingdom six months ago. While they spoke, Swee'Pea went back outside, only to run into Snagg again, but having had enough of his kidnappers, Swee'Pea was quick to let them have it with his own spinach empowered might, forcing Snagg to retreat once more. When Swee'Pea went back inside, Mouser had already explained all the details to Popeye and even showed him a picture of the suspected thieves, with their mugs eventually recognized by Swee'Pea as the same individuals that were trying to kidnap him.
Meanwhile, in the front yard, Snagg and Baby Doll tried another scheme by luring Swee'Pea into a pit trap as soon as he walked out the front door after they knocked, wherein he would be left secured inside a leather sack. As soon as the front door opened to their knocking, their supposed intended target fell in the pit trap's bag and they quickly ran off with him back to their hideout. When they made it back, however, it was revealed to be actually Popeye who had fallen in, and he quickly gave the two brutes the beating of their lives and also took them back to his home for Mr. Mouser to apprehend. Once caught and threatened by Popeye and Swee'Pea, the now frightened duo revealed what they had done to Swee'Pea's back six months earlier, and the invisible ink on the boy's back was made visible after his ingesting some warm water as the crooks instructed, thus securing the location of the "map" as being none other than Swee'Pea himself. With the crooks arrested and the royal jewels confirmed safe, Mouser went on his way, although Popeye was forced to pay for his delivery back to Spinachovia.