mellored
Legend
It's not what you land on, it's surface area vs weight. It's how parachutes work.RAW doesn't seem to have anything preventing the falling damage on a snail, but the Sprite could just cast fly on my eldritch knight (20 Strength) who grapples the enemy then flies as high as he can and drops the enemy on a boulder (providing for a not soft surface).
Smaller animals get the same effect for free. Their surface area is much bigger compared to their weight. So their body acts as their own parachute.
So a more realistic thing would be like...
30d6 for large creatures.
20d6 for medium creatures.
10d6 for small creatures.
no damage for tiny or smaller.