You show obvious outward signs of your arcanowave corruption. Occult tattoos that leer at onlookers, clawed fingers, eyes like the void or that glow red are common examples. This makes normal people very afraid of you and those in the know aware of the fact that you are mutated.
The exact manifestation of stigmata varies from person to person, and even from moment to moment. But it cannot be disguised by magically changing your shape; the stigmata are a part of your magical identity and stay with you however you change your shape and appearance.