Perfectly Rounded:
I guess Winnie The Pooh or Homer Simpson would be great!
And actually I first thought about Santa Claus but maybe that's not the best option for halloween 😆
Effervescentfetish:
You could go as Santa but with a Jack-o'-lantern theme or colour scheme lol
Santa Claus a la Tim Burton style.
Maybe not the version in
The Nightmare Before Christmas because that guy isn't spooky at all:

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Maybe something that looks more at home in
The Corpse Bride?