Chasing my children around with a mouldy pumpkin seemed a good idea at the time, writes Jo Malone

How to explain to an eight year old that Halloween isn't just about collecting sweets from strangers isn't easy. Nor is explaining that on this one night a year it's fine to ignore everything she's been taught about stranger danger.

When that eight-year-old has a lot of questions, and also a lot of nightmares, it's almost impossible.

For this ghost-believing child I don't want to talk too much about the ancient Celts believing the boundaries between the worlds of the living and the dead came down for a night and that the ghosts of the dead came back to earth.

Or that the Romans added their spin on the night by combining commemorating the passing of the dead with a festival honouring Pomona the goddess of fruit and trees and that later the Christians gave it their twist with All Souls Day, a day to honour the dead.

'What do you mean the dead passed?' asks Thalia, as I start to get too involved and wish I hadn't looked up the history of Halloween.

I read out bits from a quick Internet search saying that a long time ago the Druids built bonfires and wore costumes during their celebrations and the Christians had bonfires too, but I knew I was making little sense when I said Irish immigrants taught the Americans about dressing up in costumes and going from house to house asking for food and money and that's why we trick or treat.

I said I thought the costumes were something to do with being in disguise so ghosts wouldn't recognize them and treats were offered to keep the spirits happy, but I'm not sounding convincing. For once I'm relieved when she changes the subject and asks when she can learn the violin.

For trick or treating we head into town; with Thalia a hissing vampire which keeps transforming into a zombie, copying Daddy-zombie Rob who drags himself around the streets, making very odd, horrible noises. (A friend later comments that it sounds like a normal night for us.) Keola's a cat, more cute than scary, but loving the atmosphere of everyone dressed up.

We're still talking about Halloween this week and notice that one of our pumpkins has gone very mouldy, naturally it becomes 'Mouldy Man' and I chase the girls about with it, borrowing from Rob's catalogue of odd zombie noises. They scream, a lot, it's very funny – until Rob points out they'll have nightmares.

Thalia wakes up terrified that night and I'm feeling awful, until she says it's not Mouldy Man in her dream but she's convinced earwigs are crawling over her bed. She calms down; it felt real but there are no earwigs, she understands they don't like beds and we all go back to sleep – and I dream of earwigs crawling from mouldy man, making horrible zombie noises…