so here's my idea and how it would work, if flying around inside a building or above ground and you want to go through the ground to a cave or through a building you can just punch while in flight mode and you'll dematerlize allowing you to go through the blocks as if your in spectator mode then to land you must remateralize first

I'd back that idea, it sounds pretty cool! 

cool, i like that idea was about to suggest one exactly like that!

I love that and it’s got a great mechanic for people either in single player and want to have some fun or in multiplayer on either there server or there friends or somethings so they can use it to get through there friends house or building where there at.