Final answer:
In the second Halloween episode, the main characters dressed up in costumes that maintained anonymity and alluded to black-and-white crosswalk patterns.
Step-by-step explanation:
In the second Halloween episode, the main characters on the show dressed up as different costumes that served to both maintain anonymity and allude to black-and-white crosswalk patterns. While a comprehensive list of costumes is not available from the given information, it can be inferred that the costumes were likely creative and unique.