Chromatic Rage

You conjure a portal 15 feet in diameter in unoccupied space from which heads of five adult chromatic dragons poke out to use their breath attacks. Portal must be created on flat surface, but said surface may be temporary and magical in nature. Dragons perform their attacks simultaneously according to rules below:
Acid Breath. The dragon exhales acid in a 60-foot line that is 5 feet wide. Each creature in that line must make a Dexterity saving throw against your spell save DC, taking 54 or 12d8 acid damage on a failed save, or half as much damage on a successful one.
Lightning Breath. The dragon exhales lightning in a 90-foot line that is 5 feet wide. Each creature in that line must make Dexterity saving throw against your spell save DC, taking 66 or 12d10 lightning damage on a failed save, or half as much damage on a successful one.
Poison Breath. The dragon exhales poisonous gas in a 60-foot cone. Each creature in that area must make a Constitution saving throw against your spell save DC, taking 56 or 16d6 poison damage on a failed save, or half as much damage on a successful one.
Fire Breath. The dragon exhales fire in a 60-foot cone. Each creature in that area must make a Dexterity saving throw against your spell save DC, taking 63 or 18d6 fire damage on a failed save, or half as much damage on a successful one.
Cold Breath. The dragon exhales an icy blast in a 60-foot cone. Each creature in that area must make a Constitution saving throw against your spell save DC, taking 54 or 12d8 cold damage on a failed save, or half as much damage on a successful one.
Caster chooses direction and type of the attacks. These attacks cannot overlap. If it is impossible for any dragons to use their attacks without overlapping another attack, they do not perform their attacks. Multiple attacks cannot harm same creature. Attacks' areas of effect must be calculated from the edge of the portal or its' surface.
If any creature or object passes through portal, it gets transported to the location of one of the summoned dragons of DM's choice. Creatures bigger than Huge cannot pass through portal. Objects of monetary value or with magical properities will be claimed by one of the summoned dragons of DM's choice. If cast against Aspect of Tiamat, spell automatically fails.