Halloween became unsettled for me after the ninja, drifting from one cultural reference and conceptual pun to the next, eventually clinging onto whatever the group was going to do. It took more than a decade to find something real to go as.

In a souk in Marrakech, I met a man wearing a robe similar to the ones I'd been eyeing. He asked how much I had to spend. I told him only 350 dirham, but had no desire to buy a costume. "These aren't costumes," he corrected me as we left the shop and took an elaborate path towards what felt like the medina's inner sanctum. An hour later, I had spent 300 DH for a sand-colored djellaba, which hung down below my ankles, and 70 for yellow babouche. The shopkeeper indicated that I should pick out a hat. I reached for a fez. He shook his head. "That's for tourists. It doesn't go with this djellaba." Ahmed, the man, who brought me, put a taqiyah in my hands. His unflappable demeanor became a little bit crushed when I began folding up my new garments. "Aren't you going to wear it?" he asked.

As I unfurled the robe over my cargo shorts and t-shirt, my shoulders seemed to straighten. I walked slowly. Ponderously. Ahmed pulled the baggy hood over my head. For the rest of the afternoon, I slipped through the medina without a second look. It was a kind of camouflage. I ended up drinking tea with Ahmed several times that week. He fed me a complex background story for the Berber from the Atlas Mountains.

But if you had to truthfully categorize my Berber, it was a last-minute costume. The djellaba had been abandoned in my closet for a couple of years, until a last-minute Halloween invitation that required more than a token effort at costume. I left the prayer cap at home that night, and didn't correct anyone who assumed it was a Star Wars thing. I also felt the most visceral sense of a soul I had encountered since Morocco.

It was out of laziness that the Berber from the Atlas Mountains reappeared the next year. I took on more of Ahmed's mannerisms this time. I began adding lines of dialogue right out of the medina, filling in the blanks with Wikipedia and Alberto Ruy Sanchez poetry.

And so as the character was brought more vividly to life each year, I learned to make pumpkin tagine and use the Obi-Wan hood to smuggle miniature Coffee Crisps. I began listening to a punk band called Mongoose, whose lead singer wrote a vest pocket book called "10 Steps to a Life Uniform" in which he likens the effect of finding a permanent costume to "that feeling when people order for you and it is exactly what you wanted." At which point I realized that I'd never wear any other Halloween costume.

None of this quite answered the question: Why do we dress up?

In my case it was the chance to tell a joke about a mouse and a cat, which Ahmed had told to everyone we met that week in Marrakech. "The cat chase the mouse around...the medina," he would always start, his face and shoulders scrunching to invoke both the concentration of the cat and the mortal fear of its prey. (You could see tables and stools and giant pyramids of saffron fly left and right in their furious wake.) "Chase and chase and chase...and chase," Ahmed would shriek, "until finally the mouse find the place in the wall where the paw of the cat cannot reach...what do you call it?"