Phil and Limor from Adafruit write, “Make your own flexible, spiky, glowing accessory using NeoPixel strip diffused by NinjaFlex flexible 3D printing filament! Magnets let you attach the spikes to anything in your wardrobe. The soft flexible enclosure holds GEMMA, the tiny microcontroller that animates the LEDs, and a rechargeable lipoly battery.”
(Thanks, Pt and Limor!)