Soft sand

Soft sand is a type of Semisolid Platform that can be destroyed. It first appeared in Yume Kōjō: Doki Doki Panic and Super Mario Bros. 2 where it is found in the deserts of World 2 and World 6. Mario and his friends can dig the sand directly under their feet using as long as they are not carrying anything with their hands.

Soft sand reappears in World-e of Super Mario Advance 4: Super Mario Bros. 3.

In Super Mario Maker 2, SMB2 Mario can dig Cloud Blocks as if they were soft sand.