Honey Block

Honey blocks are sticky blocks craftable from honey bottles.

Obtaining
Honey blocks can be broken instantly, regardless of held items.

Usage
Entities touching the side of a honey block fall at a slower speed and do not take fall damage, similar to going down a ladder.

When pushed by a piston, entities on its top surface and adjacent blocks move with it. Mobs are not launched high in the air if a piston pushes them up, unlike the slime block's behavior.

Mobs avoid walking on honey blocks.

Unlike the slime block, the honey block does not carry a redstone signal.

Slowing down entities
Honey blocks slow down entities walking on top of them and prevent them from jumping. Players, who can ordinarily jump about $1 1/4$ blocks high, can only jump about $3/16$ blocks high on honey. They can more easily step up onto other blocks than jump up onto them.

Falling
As with hay bales, falling onto a honey block reduces the fall damage by 80%, i.e. the player or mob takes 20% of the normal fall damage.

Bees
When placed near beehives or bee nests, bees will occasionally fly close and attach to it for a few seconds, resembling an action of "eating honey". When doing this, a bee stops flattering wings and firmly attaches its face to a honey block.

This is regardless if there is any flower around.

Trivia

 * Honey block is 1 pixel shallower than a full block on the top (like soul sand,) and on each side. (Only within this 1 pixel range can a player "stick" to it and slide down vertically.)
 * In real life, bees do eat honey when temperature is low and flowers are difficult to find. Otherwise pollen is their primary food.