A creature is heavily obscured when something makes them impossible to see. Examples include total darkness, thick fog, or a heavy smoke.
- A heavily obscured creature has advantage on stealth checks.
- A heavily obscured creature has advantage on attack rolls and attack rolls against them have disadvantage.
- A heavily obscured creature cannot be seen or targeted with spells that require the caster to see the heavily obscured creature.
- Often, a creature that is heavily obscured is also blind to their surroundings.