I would look at Hooke's law regarding spring physics. You can accomplish a jelly effect with that equation.
Here's a capx I made using the equation: https://onedrive.live.com/redir?resid=7 ... ile%2ccapx
I used it to create a jelly effect.
edit: oops, just noticed this is in construct classic: anyways, here's the equation:
k: how strong the spring is.
x: the distance between objects.
v: velocity of attached object.
Self.vel = (-0.5*(Self.X-Sprite.X)-0.1*Self.vel)
Self.X += Self.X+Self.vel