Modify (strech) one object by moving another object Having 2 cube objects A and B.
I would like the cube B to be stretched if I move A away.
So the object A should be grabbed/linked/connect to some vertices in B.

In this way I do not need to reshape object B (in Edit mode) so it fits together with object A.

How do I do this?
You could use hooks: select B and then A, then go to edit mode (of A).
select the A face near to B and add a hook to selected object (CTRL-H).

Now, when you move B, A will be stretched, since you're thus moving the hooked face of A, through B.

Eg: