Hank the "septopus" was a lot harder to create than people can imagine.
Hank, the octopus, is the first kind of animation that Pixar's ever done. It was a back and forth collaboration between art and animation to get the tentacles just right. It took about a year to create a Hank that was worthy of showing it to the directors.
One shot of Hank alone took six months to create. (Spoiler: it's the tank scene).
Hank is the hardest kind of animation the studio has ever produced.
Since they placed the mouth at the bottom of Hank's face (nearly invisible), the animators gave more expression to Hank's eyes and brows.