Shere Khan intimidates Kaa, the python, in this scene, after the snake just stated: "I was just curling up for my siesta."
Before reaching out for Kaa's neck, animator Milt Kahl has the tiger scratch his upper muzzle. It is a terrific piece of acting, which reveals Shere Khan's arrogant confidence as well as a bit of boredom.
Milt pulls the mouth way down in order to create a clear space for the scratching action. The elongated face should look strange, but it doesn't. Milt's master drawings actually expose character comedy.
These are copies of his key drawings for the scene. I grabbed them from a model sheet, so the images aren't hi res, but still fun to study. It's interesting to see Milt indicating stripes only here and there, the rest was left to assistant Dave Michener.