They reappeared in the World Premiere Toons "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 far too primitive to devise a crime above the level of littering or jaywalking (in contrast to the original short, 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); indeed, they considered stealing an orange to be their greatest crime ever (in the episode "Divide and Conquer").
They are definitely Townsville's least malicious villains, even having a friendship-of-sorts with The Powerpuff 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 a vaccine he soon dispensed to the town, curing them just as quickly.
The biggest act of villainy they've ever committed was successfully stealing every orange in town, which caused everyone to get scurvy. They were able to do this when seeing an orange split into it's segments triggered something in their minds which made them undergo Mitosis and divide to great numbers. Fortunatly the girls were able to merge all the copies back into the original criminals and locked them up.
The boys are number 8 in the top ten worst villains.