More accurately, it's a brief eye-centered morph. I wonder if this morph is meant to be part of a much longer transformation scene.
Here's a humanized turtle film that doesn't feature ninja turtles:
>"The Red Turtle" is dialogue-free, aside from the hero’s occasional inarticulate shouts of frustration and rage . . . . The castaway builds a raft and tries to sail back to civilization, only to have his journey stopped before it begins by a giant red-shelled sea turtle, which destroys his makeshift vessel—and each subsequent one he constructs. Man and reptile stay locked for weeks in a strange standoff, until, about halfway through the film, the sailor awakens to discover that his reptilian foe has been transformed into a beautiful woman . . . .
I wonder if the new film will feature a significantly different transformation sequence. "An American Werewolf in Paris" used an odd "backward knee" design for its CGI morphs.