First place a sticky piston 1 block up in the air (basically so you have empty space underneath it), then a block on the end of it. After that, put a lever somewhere near the piston so you can control it, and leave it in the ON position (extended piston). After that, put a cobweb underneath the solid block on the end of the piston, and then put any gravity block on the solid block being held by the piston.

Now, toggle the piston so that the gravity block falls down in to the cobweb, and when it is inside it, extend it again, and you will get a weird visual glitch, where it appears the gravity block is on top of the solid block, and slightly off center. You can repeat this to make it even more off center, however, it only lasts as long as the entity is falling through the cobweb. After that the block will despawn.