Feral Ningyo's ability has two parts. Putting into play from your hand, and creating a lasting effect that returns it to the deck at the end of the conflict. There's no "then" joining them, so can that ability be activated if Ningyo is already in play during a water conflict? You couldn't put it into play again, but creating the lasting effect would be a game state change right?

Just now, Bayushi Shunsuke said:

Feral Ningyo's ability has two parts. Putting into play from your hand, and creating a lasting effect that returns it to the deck at the end of the conflict. There's no "then" joining them, so can that ability be activated if Ningyo is already in play during a water conflict? You couldn't put it into play again, but creating the lasting effect would be a game state change right?

You can trigger Feral Ningyo while it is in play to shuffle it back into your deck at the end of the water conflict.

[Tyler Parrott, May 15 2019]