When things get risky and dramatic, roll to see what happens. Grab a few d6 dice (d) equal to the stat the GM picks to test, roll them, and take the highest to determine the outcome - 6: Perfect, 4-5: Messy, 1-3: Grim.
One or two d8s (t) added to your roll by the GM to reflect a tougher than normal task. Each 7 or 8 on a thorn cuts a roll’s outcome by one step - perfect becomes messy, messy becomes grim, grim becomes a disaster.
A normal roll is +0t/tough. The GM adds thorns with their gut feeling, given the situation. They can make it +1t/very tough or +2t/extremely tough. If it’s at +3t, the task can’t be done - break it up into steps or try a new approach.
If needed, the GM can assess difficulty factors to determine how many thorns to add:
Damage to a PC also adds thorns to a roll, but they don’t count towards making it impossible.
If a grim threatens to grind the story to a halt, the GM can keep things moving - you get what you want, but in a way that makes things much worse. If a roll somehow turns out to have no effect, you learn new info or setup for a follow up.