late pelican
This was amusing - I ran bonus level 3, got a silver box, which turned out into 3, which spawned another 3, etc. all the way into the chimney on the right - so i couldn't (easily) jump up there. It was rare to see it continue that long. Amusing in a way, though having it block my jump was a bit of a hassle 😄
Screenshot to show where i couldn't go up - obviously it's not "there" now, since this is a different bonus level.
vestal fulcrum
oh yeah
it's rare, but I've been there
I wasn't the first either - it used to be able to completely block you if you needed to jump in the space where the box is (like in that column)
The next update removed the Box's collision if it has been hit.