Doomsday

A (kind of) XK-class scenario* occurs within 300 feet of where you cast it. There are six possible events that can occur, and you must roll 1d6 to find out which of these will happen:

• 1: Damnation. Fissures filled with eerie green light appear every 30 feet away from where you cast the spell and each other. Every time a round finishes (after you, your party, and your opponent's turns all end), these fissures all erupt with a geyser of green flame that deal 7d20 necrotic damage to everything in a 5 foot radius of each fissure. If a creature falls in, they are quite literally spat back out with a geyser of the aforementioned green flame, dealing the same damage.
• 2: Meteorite Rain. Meteorites begin to fall from the sky targeted at random places in the radius. After the end of a turn for any creature, one meteorite falls from the sky. Everyone who can take damage from a meteorite must, at the beginning of the spell, roll 3d100s. For every meteorite that falls, roll 3d100s. If the meteorite's roll is at least 5 away from one of the creatures who rolled 3d100s, the meteorite lands somewhere near them, and they take 3d20 fire damage and 3d20 bludgeoning damage and are pushed away 30 feet. If it is the same number as a creature who rolled the d100s, the meteorite lands directly on them, and they instead take 5d20 fire damage and 5d20 bludgeoning damage and are pushed away 50 feet. If a meteorite does not roll within 5 of a creature's roll, it falls somewhere random. If the meteorite rolls 5 away from two or more people, the DM chooses which one the meteorite damages. If a meteorite lands where it seems like another creature would be hurt, only the one who the meteorite rolls 5 or less from actually feels the effects.
• 3: Infection. A strange kind of sickness engulfs the radius. At the start of every turn for any creature, they take 5d20 poison damage and are poisoned. This effect disappears completely when the spell ends, though it can be spread outside the radius until the spell ends. Any creature that dies to this infection becomes a zombie and regains all equipment they had when alive.
• 4: Frigid Wasteland. The skies become filled with snow clouds, and the ground is covered with snow. The terrain becomes Arctic (if it isn't Underdark), and all flames, magical and not, are instantly extinguished. Azer, Efreeti, Fire Elementals, Fire Giants, Magma Mephits, Magmins, Salamanders, and Steam Mephits in the area must make a Constitution saving throw. If they succeed, they are propelled outside the radius and cannot enter again until the spell ends. If they fail, they are instantly dead. Every time a turn begins for a creature, they take 7d20 cold damage. If they have a Ring of Warmth, they instead take 5d20 cold damage.
• 5: Pure Darkness. The entire radius is consumed by darkness that cannot be dispelled by any spell except Wish. If a creature has Darkvision, Blindsight, or Truesight, the radius is halved. Every creature in the radius has disadvantage on casting spells, keeping concentration in general, and saving throws for spells. At the start of each turn, a creature must make a Wisdom saving throw. If they fail, they take 5d20 psychic damage, their turn is entirely skipped, and they cannot make reactions until their next turn. If they succeed, they instead take 3d20 psychic damage and can take a turn and reactions.
• 6: Reroll. Roll another d6 for the events above. All damage taken in this instance is increased by 1d20 of the corresponding damage type(s).

The caster of the spell is not affected by the events from the spell. They do not take the corresponding damage, do not roll the 3d100s for the Meteorite Rain, and are completely immune to the effects above. The creatures inside must continue to make turns as if they are fighting someone, even if they're not, while inside the radius.

*look it up