Juugo Sennin Mode.
Juugo can do sennin mode/curse seal mode.
However, this mode, doesnt seem to be linked to, or taught by one specific animal.
Naruto had the toads teaching him for example.
I believe the Juugo clan sennin mode, has a wide array of animals, like the mode forms into your inner animal or summoning animal.
We have seen that Kidomaru turned into some sort of spider, when he went full curse seal mode.
A spider was his animal summon.
Sasuke, one who can summon birds/hawks, turned into a hawklike being in his curse seal mode.
The blackness on his nose representing a beak and the giant claws on his back, representing wings(and claws).
So, Juugo his sennin mode, shapes you to an animal, that you are most connected with.
It seems like this is the case.
Look at the variety of different looking animal forms.
I feel like we are gonna hear more about this mode.
One of the reasons being the revelation of the Juubi and nature chakra.
What do you think?