This spell was developed by Ori during his years alone in hiding. It draws upon the magic of the Feywild to transform the caster not into a different person entirely, but into an altered version of themself, with certain constraints. For example, it cannot make the entire structure of antlers disappear, only make them appear like horns. As long as the caster keeps a steady mind and connection to the Feywild, they can keep the spell held for a good while, but sudden shock will cause it to flicker, and an attack will cause it to disperse entirely.
The changes wrought by this spell fail to hold up to physical inspection. For example, if you use this spell to add a hat to your outfit, objects pass through the hat, and anyone who touches it would feel nothing or would feel your head and hair. If you use this spell to appear thinner than you are, the hand of someone who reaches out to touch you would bump into you while it was seemingly still in midair.
To discern that you are disguised, a creature can use its action to inspect your appearance and must succeed on an Intelligence (Investigation) check against your spell save DC.
As Ori has only ever used the spell to transform from a deerfolk into a tiefling, he is unsure what other properties it has.