A crack forms below you… and suddenly a tunnel collapses inward beneath your feet.
After a short while your fall is arrested. You are now snagged in a web, in the dim light lit from where you fell you can see this web goes on, all around you, seemingly forever.
Roll for intelligence… 16. The progress of the one hit BEG killing spell is 33%
<many turns later>
Roll for intelligence… 3. The progress of the one hit BEG killing spell is 96%. That’s the only action you can take on your turn. You better hope the party can stop the army from hitting the power source of this spell before it finishes.
Roll for intelligence… 5. Since that would be more than 100 the progress of the spell rolls back to 91%.