Incomplete Metamorphosis

An incomplete metamorphosis occurs when a metamorphosis is interrupted in several ways, whether the individual suffers extensive damage, infection, etc. while undergoing metamorphosis that their transformation would be affected, or their transformation was simply too complicated and errors occurred mid-transformation.
This leads to metamorphous defects, manifesting in abilities that are more likely to harm the user, lack in power potency or control, improper mutations, cognitive and behavioral disorders, etc.