This would lead to the obvious problem that they would forget that they were a wizard and be trapped, unknowingly, in this form for the rest of that creature's lifespan unless transformed back by another wizard.
Esto daría lugar al obvio problema de que olvidaría que es un mago y estaría atrapado, sin saberlo, en esta forma por el resto del tiempo de vida de esa criatura salvo que sea transformado nuevamente por otro mago.