No, I have no Halloween costume.
There are many ways to frighten people or kids off - or to entertain them - lol.
There are also many horror movies referring to Halloween.
Great Britain, namely Ireland, Scotland and Wales, is celebrating Halloween.
And there's also Guy Fawkes Night, https://en.wikipedia.org/wiki/Guy_Fawkes_Night
to remember English history.
Continental Europe, is commemorating namely All Saints Day (an official holiday without masks and costumes) and various other events with costumes and masks, like Carnival, harvest and other festivals, of course:
https://en.wikipedia.org/wiki/Carnival_of_Venice
One of our own big events is the Carnival of Basel:
the https://en.wikipedia.org/wiki/Carnival_of_Basel
or big harvest and similar events, like the Oktoberfest of Munich
or the Fête des Vignerons in Vevey:
https://en.wikipedia.org/wiki/F%C3%AAte_des_Vignerons