I know this post is from 2017, but I find that discovery amazing, as it would have been a very powerful, end-game, multi use tool, that would have been really balanced, as there are a more or less limited number of shulker boxes you can actually get in an average gametime. I said would because I tested it and doesn't work anymore, at least in 1.13.2. Now, the bounding box of the shulker just updates and you, or whatever that is above, just gets pushed upwards a bit. Sadly, this (freakin' amazing mechanic) has been nerfed/fixed.
In fact, I think this could have been worked on or just kept, like that redstone block activation bug of the pistons, that started as a bug and has finally become vanilla as it was milked by the community. But, a pretty rare block, very hard to get and that can temporarily get untangible? Would have been neat, even if the mechanic had been ported to another block. Pistons don't work any similar to this at all, they are far more easy to spot and hear, they make miniaturisation harder and sometimes their aesthetics just don't work.