"As the horror withdrew its tendril, so a strange numbness and warmth spread through me. The pain I expected was not there, and in its place was a glowing sense of relaxed nothingness. I actually smiled, and only avoided being decapitated when I stumbled over my companions body, and fell backwards out of the way."
- Andriss Vorge, Adventurer
4th Edition Version: A numbed character can no longer feel pain, and is infused with a slight state of dissociated calm, which stops them being able to understand the extent of their wounds and makes them less swift to react. In game terms, the player no longer tracks their character's hit points, the GM doing this (in secret) instead. They also suffer a -2 penalty (per tier of the effect inflicting the condition) to all Dexterity based checks.
5th Edition Version: GM tracks hit points as above, and target suffers disadvantage on all Dexterity checks and saving throws.