Randy Zane is a teenager who beat up Dewey and Reese quite easily. Randy's intentions were actually a mistake, (he thought one of the boys to be someone he was meant to beat up). Malcolm got out of this due to them revealing that none of them were the person he was looking for.
Randy for most of the episode is never really seen until the very end, most of the episode he waits outside for one of the boys to beat up.
Not much is known about him personally, aside from being extremely patient (Randy waited outside of the boys' house for several hours and maybe even days without food, water or sleep).
He is also capable of extreme violence, seeing as how he was able to destroy a frying pan just by punching it and knock out most of Dewey's teeth.