Dragon's Lair

Upon casting, choose a dragon type. In a radius of 120ft, centered on the caster at the time of casting, the caster can determine an effect based on the dragon type selected. The type of dragon determines the effect the lair will have. If an effect requires a save, use your spell save DC. If the spell requires a ranged spell attack roll, use your bonuses. Each effect takes place immediately following the caster's turn, winning initiative ties.

Red: A point within range that you can see, a steaming hot geyser erupts in a 15 ft. diameter. Each creature must succeed a Dexterity saving throw taking 6d6 fire damage on a failure, or half that on a success.

Blue: Lightning arcs, forming a 5-foot-wide line between two of the lair’s solid surfaces that you can see. They must be within 120 feet of the dragon and 120 feet of each other. Each creature in that line must succeed on a Dexterity saving throw or take 3d6 lightning damage.

Black: Immediately following your turn, a cloud of swarming insects fills a 20-foot-radius sphere centered on a point the caster chooses within 120 feet of it. The cloud spreads around corners and remains until the caster dismisses it as an action, uses this lair action again, or dies. The cloud is lightly obscured. Any creature in the cloud when it appears must succeed on a Constitution saving throw, taking 3d10 piercing damage on a failed save, or half as much damage on a successful one. A creature that ends its turn in the cloud takes 3d10 piercing damage.

Green: Grasping roots and vines erupt in a 20-foot radius centered on a point on the ground that the caster can see within 120 feet of it. That area becomes difficult terrain, and each creature there must succeed on a Strength saving throw or be restrained by the roots and vines. A creature can be freed if it or another creature takes an action to succeeds on a Strength check.

White: Jagged ice shards fall from the ceiling, striking up to three creatures underneath that the caster can see within 120 feet of it. The caster makes one ranged spell attack roll against each target. On a hit, the target takes 3d6 piercing damage.

Gold: The caster glimpses the future and can warn one creature it can see within range so it has advantage on attack rolls, ability checks, and saving throws until the end of that creature's next turn.

Brass: A strong wind blows around the caster. Each creature within 60 feet of the dragon must succeed on a Strength saving throw or be pushed 15 feet away from the caster and knocked prone. Flying creatures have disadvantage on the save, and if they fail, they drop 60 ft., or until they hit the ground taking 1d6 bludgeoning damage per 10 feet of falling. Gases and vapors are dispersed by the wind, and unprotected flames are extinguished. Protected flames, such as lanterns, have a 50 percent chance of being extinguished.

Bronze: A thunderclap originates at a point the caster can see within 120 feet of it. Each creature within a 20-foot radius centered on that point must succeed on a Constitution saving throw or take 3d10 thunder damage and be deafened until the end of its next turn.

Copper: The caster chooses a point on the ground that it can see within 120 feet of it. Stone spikes sprout from the ground in a 20-foot radius centered on that point. The area becomes difficult terrain, and movement is quartered. Creatures that move within this space take 4d4 piercing damage for every 5 feet of movement.

Silver: A blisteringly cold wind blows through the lair near the caster. Each creature of the caster's choice within 30 feet of the creature must succeed on a Constitution saving throw or take 3d10 cold damage. Gases and vapors are dispersed by the wind, and unprotected flames are extinguished. Protected flames, such as lanterns, have a 50 percent chance of being extinguished.

Amethyst: The caster chooses a space it can fit into within the lair. It exists in its own space and the chosen space simultaneously until the start of the caster's next turn. Whenever it moves or takes an action, it chooses which version of itself is moving or acting. If an effect or attack can target both of the caster’s spaces at the same time, the caster is affected only once. The caster can move its speed and use actions/bonus actions/reactions divided among itself and its projection. The caster can choose to cast a spell from either itself or the projection. Whenever an effect would target the caster or its projection, roll a d20 - on a roll of 13 or more the attack misses.

Crystal: The caster chooses a point it can see in the lair. Gleaming starlight radiates from that point to fill a 10-foot-radius sphere with dim light. Each creature other than the caster in that area when the light appears must succeed on a Dexterity saving throw or take 2d12 radiant damage and be outlined in the glow, or half as much on a success and not be outlined. Attack rolls made against an outlined creature have advantage, and the creature can’t hide or benefit from being invisible. This effect lasts until the start of the caster's next turn.

Emerald: The caster attempts to alter the perceptions of one creature it can see within its lair. That creature must succeed on a Intelligence saving throw or take 4d10 psychic damage and have disadvantage on saving throws until the start of its next turn.

Moonstone: The caster targets a creature it can see in its lair, and a merry waltz begins to play that only the target can hear. The target must succeed on a Intelligence saving throw or dance until the start of the caster's turn. The dancing creature is incapacitated and must use all its movement to dance.

Sapphire: A thunderous detonation of sound that can be heard up to 300 feet away surrounds one creature in the lair that the dragon can see. That creature must succeed on a Constitution saving throw or take 3d8 thunder damage and be stunned until the end of its next turn, or half as much on a successful save and not be stunned.

Topaz: Up to two creatures the creatures the caster can see within the lair must each succeed on a Constitution saving throw or take 4d6 necrotic damage or half as much damage on a successful save. Negative energy infuses the creatures that are affected and cannot regain hit points until the start of the caster's next turn.