This is sparkle poi! Poi was created in New Zealand by the Maori people. It is the rhythmic spinning of weights on string. Modern versions include glow poi and sparkle poi. Glow poi uses LEDs or glowsticks to create colorful patterns, and sparkle poi uses lit steel wool. As the steel wool burns, parts fly off causing the effect seen above. I would guess a blue filter has been added, as it normally looks like this
it may be steel wool mixed with like copper chloride or something. still pretty cool
isabela: i keep telling you, kitten, get a pair of proper boots. like mine! merrill: i can’t, i just can’t. your boots go on forever, i’d get so lost in them. i’ve dropped marbles in them, they take an eternity to reach the bottom! isabela: …that’s the reason I’ve been finding marbles in my boots?