Blue Dragon

Regional Effects

Source: Monster Manual (2024)

The region containing an adult or ancient blue dragon’s lair is changed by its presence, creating the following effects:

• Sinkholes. Sinkholes form more frequently in the area within 1 mile of the lair. Whenever a creature in that area other than the dragon and its allies finishes a Long Rest, roll 1d20. On a 1, a sinkhole opens beneath the creature, and the creature must succeed on a DC 15 Dexterity saving throw or fall 2d4 × 10 feet into the sinkhole.
• Spiteful Storms. Dust devils and thunderstorms rage within 1 mile of the lair. The area is Lightly Obscured.

If the dragon dies or moves its lair elsewhere, these effects end immediately.