Did you know that stretch effect is possible in vanilla scratch? Well, it is! If you click see inside, you will see three new blocks. Try putting different values in them and have fun! You can remix this project to use stretch in your project! But if you do so, please give credit to me. To use stretch, go in the costume editor and notice that around the cat, there is a giant, transparent box. To replicate that, in your project, draw a large perfect square around the sprite which fills the whole screen. Then, bring it up so that its baseline and the sprite's baseline is the same. Then, the stretch blocks will work.
Thanks to @griffpatch for the idea. I didn't exactly copy his code from his tutorial but the idea is the same DISCLAIMER- THE STRETCH EFFECT ONLY WORKS TILL 99, AFTER THAT IT BECOMES A WEIRD LINE.