Falling Block

A falling block is an entity form of block that appears when a gravity-affected block loses its support.

Spawning
Falling blocks spawn where gravity-affected blocks lose their base of support. These blocks include:

Behavior
A falling block continues falling until it lands on another block. If the block it lands on is solid, then the falling block returns to its block state. If the falling block lands on a non-solid block (such as a torch), it breaks and drops as an item.