My logical deduction : the character falls (some invisible failed check) when passing on difficult terrain.

It is only a guess / hypothesis, as it is not combat/attack/hazard damage.
Unless rocks fall from the sky or ceiling.
Or unless the tadpole gets angry at us when we do not use it (like causing internal concussion). That last idea is for laughs.

Last edited by Baraz; 13/10/20 04:30 PM.