[GLITCH] Invisible Water Tank

In Granny Canyon, getting punched (by the whack-in-a-box) to enter the water tank and getting punched after you enter the tank have very different results. If you enter the tank and then get punched, you'll be able to walk around normally even before the tank starts to open.

Like most other cutscenes, Taz is placed at a certain location when it starts, but on this one you are also put in some sort of cutscene state that usually wears off when the tank starts to open up.
By getting punched (whenever a box notices you, it will always punch you after a set amount of time, wherever you are in the stage), you are forcibly removed from that state, allowing you to move around while the rest of the cutscene plays out. I'm still not sure why this makes the water tank invisible, sorry. =P

The best way to get this glitch to happen is to enter the tank from the left part of the post holding the tank and jumping in from the side.