Dracona Meteoris

You coat your arrow with the blood of dragons, infusing it with the Dracona Meteoris, the spirit of the one true dragon. The next time you make a ranged weapon attack for the spell's duration, instead of choosing a target, you choose a point within the weapon's range. You shoot the arrow into the sky where the arrow transforms into pure energy giving off bright light around it for 50 feet on all directions. You call upon the spirits of all the dragons you have ever slain and infuse the arrow with them. The arrow falls to the earth at the point you chose, bringing with it 1 meteor for every dragon you have ever killed and piercing through any cover that is not reinforced with extremely durable material. The arrow and meteors hit the ground creating a variety of elemental explosions with a 50 ft radius. The damage type of the explosions corresponds with any dragons you have killed using the following list. All types apply simultaneously, all applying against a hit creature's weaknesses, and resistances. Any immunities of a hit creature are treated as resistances. Any creature directly hit by the arrow (the point initially chosen) makes a dexterity saving throw ignoring any effects or benefits of their shield and/or armor. On a failed save the creature takes your weapon's attack damage as radiant damage + 1d4 of each corresponding damage type. On a passed save a creature takes half. Any creature within the range of the explosions, including the one hit by the arrow, must make a dexterity saving throw. On a failed save, a creature takes 1d4 of each corresponding damage type. On a pass they take half. 

Compare the following list with dragons you have killed to determine how much damage, what damage types, and what effects to apply.

Fire:

• CR1 or higher dragon that can deal or has resistance to fire damage- Damage type becomes fire
• CR5 or higher dragon that can produce fire breath- This attack ignores fire resistance 
• Adult (or older) dragon that can produce fire breath- Any creature that fails its check permanently gains fire weakness before damage is rolled.

Cold:

• CR1 or higher dragon that can deal or has resistance to cold damage- Damage type becomes cold
• CR5 or higher dragon that can produce cold breath- This attack ignores cold resistance
• Adult (or older) dragon that can produce cold breath- Any creature that fails its check permanently gains cold weakness before damage is rolled.

Lightning:

• CR1 or higher dragon that can deal or has resistance to lightning damage- Damage type becomes lightning.
• CR5 or higher dragon that can produce lightning breath- This attack ignores lightning resistance
• Adult (or older) dragon that can produce lightning breath- Any creature that fails its check permanently gains lightning weakness before damage is rolled.

 Acid:

• CR1 or higher dragon that can deal or has resistance to acid damage- Damage type becomes acid
• CR5 or higher dragon that can produce acid breath- This attack ignores acid resistance
• Adult (or older) dragon that can produce acid breath- Any creature that fails its check permanently gains acid weakness before damage is rolled.

Poison:

• CR1 or higher dragon that can deal or has resistance to poison damage- Damage type becomes poison
• CR5 or higher dragon that can produce poison breath- This attack ignores poison resistance
• Adult (or older) dragon that can produce poison breath- Any creature that fails its check permanently gains poison weakness before damage is rolled.

Thunder:

• CR1 or higher dragon that can deal or has resistance to thunder damage- Damage type becomes thunder

Necrotic:

• Lesser (or greater) Death Dragon- Damage type becomes necrotic
• Greater Death Dragon- Double this spell's damage if creature is undead

Radiant:

• CR1 or higher dragon that can deal or has resistance to radiant damage- Damage type becomes radiant
• Young (or older) Crystal dragon- any creature that fails its save is blinded until the start of your next turn

Psychic:

• CR1 or higher dragon that can deal or has resistance to psychic damage- Damage type becomes psychic
• CR10 or higher Emerald, Topaz, or Sapphire dragon- Any creature that fails its save is charmed for 1 minute or until damaged

Force:

• CR1 or higher dragon that can deal or has resistance to force damage- Damage type becomes force
• Young (or older) Amethyst Dragon- Any creature that fails its save it pulled 10 ft toward the mid point of the affected area
• Adult (or older) Time Dragon- Any creature that fails its save disappears and reappears when 2 rounds have elapsed in the same spot where they left.