as you may know, i use fusion 2.5, as far as i can tell it has no effects system, so i just ended up creating an object (trail piece) every 1 in 5 times the movement loop was run, then i have them constantly scale down until .25% size (while moving) or .4% while dashing. i also destroyed every odd tail piece, and the ones not touching other tail pieces, all to make it more optimized. it is still very much a super poorly optimized system, but i know of no other way of doing it.