Final answer:
Michael Scott mistakenly believes Diwali, which is a major Indian festival, to be akin to Halloween in the episode titled 'Diwali' from the television series 'The Office'.
Step-by-step explanation:
In S3E6 "Diwali" of the television show The Office, Michael Scott mistakenly believes Diwali is an Indian version of Halloween. Michael, who is known for his frequent misunderstandings and cultural faux pas, is invited to the Diwali celebration by his colleague Kelly Kapoor. His confusion leads to awkward situations when he arrives dressed in a suit but mistakenly believes it is a costume party.