Well, this is the way we always dress, dear. The people who started your Halloween just imitated our traditions.
7 seconds sound clip from the Halloweentown movie soundboard.
You can hear this line at 00:37:31.575 in the Blu-ray version of the movie.
Quote context
[...]
- Now that works just like magic.
- Mother!
- Is there gonna be a Halloween party today, Grandma? Everybody's all dressed up.
- That's the way your mother ran into your father: by crashing a Halloween party!
- He loved her witch's costume.
- What are you so happy about? I thought you didn't want to come.
[...]