Why was Krang's body redesigned.

[neatoman]

Here is a trailer featuring Krang. Notice the human looking face.


And here's a clip from the actual movie. Notice how there is no top of the head or a mouth, but there is still a human nose.


At first I thought they changed because they figured it's stupid for this thing to have a human face when it's otherwise not meant to look very human, which is reasonable by the way, and that the trailer either used old footage or it was only meant to be shown in the trailer so that people would complain less... And then I noticed the nose...

So what was going on here? Did the person who modelled the nose refuse to change it? It's just so bizarre, why keep that element of all things?