The Amoeba Boys (voiced by Chuck McCann) are a gang of amoebae who were the villains featured in McCracken's original short, Whoopass Stew in A Sticky Situation, and were voiced by Lou Romano. They reappeared in the World Premiere Toons short Crime 101. With their gangster affectations, these aspiring criminals would love nothing more than to be regarded as serious villains worthy of fighting, and even getting beaten up and sent to jail by the Powerpuff Girls. Unfortunately, their brains are too primitive to devise a crime above the level of littering or jaywalking (perhaps as a consequence of A Sticky Situation, where they are seen having successfully robbed a bank and using their semi-solid bodies to stick to the girls and create a dilemma for them, solved when the girls flew them to the Sun, melting the Amoebas and their more-developed brains). Indeed, they considered stealing an orange to be their greatest crime ever (in the episode "Divide and Conquer"). The Amoeba Boys were seen in jail in the Powerpuff's Birthday Bash, so they may have done a crime worthy of jail time before, however, what they did to cause them to be in jail was not revealed. The Amoeba boys sent a gift, voodoo dolls to the girls, not understanding that they were supposed to keep the dolls, not the needles. They are Townsville's least malicious villains, even having a friendship-of-sorts with The girls. They are generally harmless, but their actions have on several occasions endangered both the girls and the town purely by accident. The greatest threat they have posed to Townsville and the girls was in Geshundfight, when they each caught a cold that, when merged with their DNA, created a severe virus that quickly spread through the city, making even the healthiest person fall ill instantaneously. It wasn't until the girls, who were also infected, acquired their DNA (after a brief and very easy fight, despite the fact they were all very sick) so Professor Utonium could create an antidote he soon dispensed to the town, curing them just as quickly. The Amoeba boys finally received the super villain status they had long craved when they used their ability as Amoebas to multiply, creating a veritable army that the girls finally stuck back together and sending the Boys to jail, much to their delight.
- Bossman, leader and general spokesman of the Amoeba Boys. He wears a gray fedora.
- Junior, the smallest one. He wears a black cap and usually repeats whatever Bossman says. In the episode "Crime 101", he is named "Tiny".
- Slim, the tallest one. He wears a brown fedora and is even much more incompetent and slow than the other amoebas. In the episode "Crime 101", he is called "Skinny Slim".