Adafruit nOOds are little noodles of light. They're as simple to use as a regular LED - connect one end to power and one end to ground, and they light up and glow. They're incredibly bendy and flexible, making them just perfect for small subtle costume details. A nOOds will last for hours on a single coin cell battery, with no big noisy EL-wire inverter to manage.
We'll also get a little crazy and hook 3 nOOds up to a QT Py microcontroller, so they can be dimmed or sequenced using CircuitPython code.
All you need to light up a single nOOds is a coin cell battery. Here are a couple in the store with built-in on-off switches, and one that includes two blink modes.
You can power multiple nOOds from a microcontroller and have a lot more control over your lighting effects. Use CircuitPython code to dim or sequence or blink the nOOds so they really sell your cosplay character. This is a more complicated project but the results can be spectacular.