An issue with a lot of similar-but-different things using similar terminology. But, I'll clarify on these things here.
Most Mythical rarity items are generated from mystery boxes. These items are guaranteed to have a random mythical effect attached to them, and will have a Mythical rarity prefix. The possible mythical effect depends on the mystery box it had been generated from, along with a few other conditions such as valid equip regions.
There are a few emissive effects that are tied to the cosmetic/skin's textures, and are always present on that item. These effects are meant to provide the player with additional information about the item. They are: Dynamic (animated 2D texture), Luminescent (glows), and Uses Hair Color.
Particle effects are attached to items that have been crafted by the player. These effects are identical to traditional non-emissive mythical effects, but the item does not have the Myth...