When you stand in the creeping moss, roll+WIS.
On a 10+, you remember to keep moving.
On a 7-9, the moss has crawled over your feet and trapped you while you weren’t paying attention. Take -1 ongoing to physical actions until you can shake it off.
When you eat the creeping moss, roll+CON.
On a 10+, you suffer no ill effects and greatly impress the nearby kobolds, who try to initiate you into their tribe.