Trick-or-treating happens after dark, and that is precisely when most pet costumes stop doing anything at all. This one works the other way round. The spider detail is luminescent, so it charges under ordinary light during the day and then shows up on an unlit street in the evening, when everybody is actually out. It is the rare novelty item that gets better as the light goes.

Glow-in-the-dark material works by absorbing light and releasing it slowly, which means the brightness is a curve rather than a constant: strongest in the first stretch after it has been sitting under a lamp, then fading over the hour that follows. Leaving it somewhere bright for a while before you head out makes a visible difference. Three sizes are listed, S, M and L, all carrying the same glowing spider design.

• Luminescent spider detail that glows in the dark
• Three sizes: S, M and L
• One design across all sizes
• Charges under ordinary household light
• Shipped tracked to the UK, typically 7 to 12 days
• Covered by our 14-day returns promise

Two things worth knowing. The glow fades over the course of an evening and needs light to recharge, so do not plan on it lasting a whole night out. And costumes are for short supervised periods only, so never leave one on an unattended dog or during rough play, and check the size guide, since chest measurement decides the fit rather than your dog's weight.

What the options mean. Sizes run from S to L — £15.99 for the smallest, £17.99 for the largest.

Who it's for: Anyone taking a dog out on Halloween evening who wants a costume that reads in the dark rather than one that disappears at dusk.