For future readers of this thread, I post here other solutions I was given:
by Rick Gerard:
T here are two ways to do that without spending some money on scripts or plug-ins. The first is with keyframes and the graph editor. It’s tedious and requires a very good understanding of the graph editor. The second is with expressions. Dan Ebberts https://motionscript.com has some links on the first page of his’ site that points to an article on Realistic Bounce and Overshoot. I suggest that you take a look there. You’ll learn more than you would if I just gave you an expression. When you get something you like save it as an animation preset.
Probably the easiest to use 3rd party solution is my friend Mathias Mole’s Squash And Stretch. There is a free version and you can get it now, but the pro version will give you a lot more options.
by Anshul Saini
1. Create any type of shapes in photoshop or after effect
2. If you’ve created your shape in photoshop than import it in after effect as a “Composition”.
3. Create a new Adjustment layer in that composition.
4. The jelly like effect works based on two simple effects – “Fast Blur” (blur in general) and “simple choker” (matte choker).
If you put both these effects on an adjustment layer, it will affect all your layers below it, so you can easily turn multiple
elements “jelly” at no time.
5. Now you have to play with fast blur and simple choker settings under effect controls.
– Adjust the fast blur value to slightly blur the shape.
– Move the choker matte value till the blur isn’t visible anymore.
Play around with those settings until you get your desired animation.
6. After doing this u can start animating your shapes or objects with position or scale keyframes.
7. You can still add new effects on the shapes or objects, it won’t affect the jelly effect as long as it stays below the adjustment layer.
Hope You get your desired effect.
I have also found this other thread that talks about a similar effect and shows a cool solution as well:
https://forums.creativecow.net/docs/forums/post.php?forumid=227&postid=7579&univpostid=7579&pview=t