When you get enough of the size increases you get that same sound if it happens to be on the other side of the doorway. It slowly collisions its way back to you with the same bonking on the wall sound. Dunno if it sometimes resets to some default position outside the playfield or whatever. Good finds, hope there will be a new version since I like using the multi power up. Skipped taking those and made it to like level 11 or so before a legit death.