I get the feeling that Pixar and other studios have borrowed a lot more than just this one scene from Looney Tunes but it’s still funny and kind of sad since the dog and Sully are both so heartbroken at the thought that the little life they were responsible for might have been smooshed, flattened, and then reformed into something so macabre that it would make them want to faint. The dog is a little more tragic since as I recall he really didn’t like the cat to start with but eventually got used to the little feline. Sully on the other hand was afraid of Boo to start with but started to get used to her after she displayed her cuteness over and over. So yes, both scenes are very similar.
If you look at any animated movie however and compare it to other animated features you might notice that certain movements, plot points, and other things are bound to be repeated again and again. It’s not plagiarism really, it’s just that ideas are easy to bounce around from place to place. Unless they become trademarked, which would be a horrible thing to do if it was applied to everything, they’re bound to be recycled and reused again and again. Ideas are always being explored, redone, and refurbished in a way that seems like it’s new and has never been seen before, but a lot of them have been seen multiple times without a lot of people realizing it. In fact some of the earliest cartoons kind of set the bar for the animated features of the recent past and even now. If you look at the plot of just about any animated movie the chances are good that you’re going to see something familiar that you’ve seen somewhere before.
Some of them are deliberate since the creators want to pay homage to the old cartoons and give them a little bit of credit for having come up with it first. Others are usually accidental and aren’t really meant to emulate anything else. The ideas of the past have been repeated so often that it could explain why some shows don’t do so well, their ideas have been seen a dozen upon a dozen times before and they went to the well one time too many to try and revive an old plot line. When that happens it’s time to step back and take a few minutes to think over what hasn’t been done to death yet and what though process might be needed to bring something that hasn’t been seen in a while back into the public eye.
Keep in mind that despite the history of film and animation that’s now available at the click of a button, a lot of the current generation don’t take the time to watch the old cartoons. So really, the ideas that are being rolled out now are thought to be original and cutting edge. A lot of us that have seen these types of things before know better, but it doesn’t hurt to let the current generation enjoy them as though they’re brand new.