There are two possible Mythical Zoans Loki could have, based on Norse mythology: Fenrir or Jormungandr, since both are his children in myth. It's either:

>Mythical Zoan Dog model: Fenrir
>Mythical Zoan Dragon model: Jormungandr

My money’s on Jormungandr though since it represents immense size and fits well with the ancient giants, who were known for their strength and power."It would make sense that, as Rocks stated, only Harald and Loki are capable of wielding its full potential.