Take care of yourself first.
Arc's basic diet consists of random praise and the satisfaction of knowing people take enjoyment from his project.
As for the beast...
Well, not like we'd ever get to see much, as showing said eldritch monstrosity would be rather counterproductive as the medium can't even begin an attempt at properly conveying what we're supposed to see (engine limitations)
So the only thing we get is an evil grin, many eyes and tentacles...
Not that scary after a bit.
The new form isn't that scary either.
At times it almost looks silly.
But think about it from the perspective of the protagonist.
This incomprehensible being that's always trying to hunt you down has started to change, turning into... well... you.
You don't get to see the MC often, due to the POV-ish nature of the game.
But there is no mistake, the beast is trying to turn into you.
As to why it's doing it?
Well...
I've no fucking clue.
Only time will tell...