D: Sigil

All iterations of [animal] should be replaced by a specific animal species when the spell is first found.

You trace your Sigil on a subject, then let a [animal] bite the Sigil. Should the victim survive without the aid of remedies, their body changes to become more bestial and they take on [dice] aspects or abilities of the same animal.

[Animal] + Aspect

Adapted from Marvels & Malisons