Falling Block Deals Damage?

I want to make a block that basically acts like an anvil, as in it has gravity and it deals damage upon landing on an entitiy

One different thing i want to do is make it always deal 20 points, (or 10 hearts), of damage.

I got the falling part working, but how would i deal the damage?

Is it even possible, and if so how would i do it?

Any help would be greatly appreciated!