Quicksand

I think quicksand should be added
It would give the possibility to make traps or hideouts in the desert, it would make the desert slightly more dangerous and diversify (I think it should fall slowly, but a bit like powder snow), I think the block should still be visible, to allow adventurers to avoid the trap.

Instead of cold, you would suffocate like when you are under water or under sand if you have your head in the loose sand

also, its sand would not fall (like a normal block)