LESSON & PROJECT FILES: https://www.sidefx.com/tutorials/magic-projectile-fx-for-unity/
Build the base projectile model, then add a ribbon using a spiral and a sweep. Learn how to set up uvs for all the parts to prepare for texturing. Once the model is ready you can export the results to FBX. This file can then be imported into Unity and set up within the VFX Graph where you will emit the projectile at regular intervals.