Unbridled Potential

You roll the bones with destiny, strum the strings of fate, and stretch the fabric of reality, calling upon the untempered strand of arcane energy that curves through the very core of your being to unleash a burst of pure chaos, affecting yourself and creatures in your vicinity.

Roll one d4, one d6, one d8, two d10s, one d12, and one d20.

Roll one d4. The result of this roll determines the number of creatures you may target with this spell. You and each target must make a Constitution saving throw as space and time warp around you.

Roll one d6. You suffer this much damage. If you failed your Constitution saving throw in the previous step, you also suffer one point of Exhaustion.

Roll one d8. The spell inflicts this much damage to each target who failed their Constitution save. Those who saved take half damage.

Roll two d10s. The spell’s damage type in the previous two steps correlates to the results of your two d10 rolls (the damage may — and often will — be of two different types simultaneously; damage of two types ignores resistances of enemies with resistance to only one of the two types of damage).

1. Acid
2. Cold
3. Fire
4. Force
5. Lightning
6. Necrotic
7. Poison
8. Psychic
9. Radiant
10. Thunder

Roll one d12. An additional effect affects each creature that failed its Constitution saving throw until the end of your next turn.

1. Blessed, via the Bless spell.
2. Blinded
3. Deafened
4. Frightened
5. Grappled (by invisible hands, DC 14)
6. Invisible, as with the Invisibility spell.
7. Poisoned
8. Prone
9. Stunned
10. They begin to Fly, as with the Fly spell.
11. Enlarged, via the Enlarge/Reduce spell.
12. Petrified, for 1d4 turns.

Roll one d20. An additional effect happens following the initial burst of energy.

1. Time pools around you and you begin to slide backwards into eternity. Roll one d20. Your character plummets through an ever-shifting, amorphous void outside of their universe or any other. A few moments — or perhaps eons — later, they arrive back in their home plane a number of years prior to their present equal to the result of your d20 die roll. Discuss the implications of this with your Dungeon Master at a later time.
2. An exact copy of each creature targeted by this spell appears in a space adjacent to the original enemy. These creatures are hostile to you and follow the same rules as the Simulacrum spell.
3. An ally within 30 ft. of you regains half their currently missing HP (rounded down) but falls asleep for 1d4 turns.
4. d12 gargantuan aquatic mammals begin to fall from 1000 ft above your position before transforming into tiny plant pots mid-descent and shattering upon impact to the ground. All creatures within 60ft must make Dexterity saving throws (DC 12) or take 4d4 bludgeoning damage.
5. All clothing and armor worn by creatures within 60ft of the caster becomes momentarily incorporeal and falls to the ground at the wearers’ feet. All bonuses to Armor Class, protection from the elements, or other benefits/penalties are not regained until the garments and gear are donned once more.
6. Your size is reduced by one size category for 1 minute, as with the Enlarge/Reduce spell.
7. You regain 3d6 hit points.
8. Your nose temporarily disappears. For 1d4 days, you are unable to smell or taste anything, and immune to effects relying on a sense of smell (such as the Stinking Cloud spell or a Ghast’s stench).
9. You are unable to coherently speak nor understand spoken languages for 1d6 hours.
10. An ally within 30ft is transformed into a sheep, as with the Polymorph spell.
11. You grow gills and are capable of breathing underwater for 1d8 days.
12. Lucky you: nothing happens (that you know of).
13. You grow physically younger by 1d10 years.
14. You physically age 1d10 years.
15. You gain a sudden divinatory insight into the near future. Until the end of combat, you gain the Diviner Wizard’s Portent ability.
16. One your eyes permanently changes to a different color. This has no effect on your sight.
17. You suffer temporary total amnesia, having no memory of your allies, enemies, abilities, or even your own name for 1d12 days. You retain basic reasoning and the ability to speak.
18. A nearby ally within 30ft (determined at random by the DM) is banished to another plane with the Banishment spell. 
19. You and the ally closest in proximity swap bodies for 1d10 days. Each character retains their memories, personalities, and mental ability scores (Int, Wis, Cha) but inherits the skills, features, and traits of their companion. While under the effects of this change, each is unable to communicate what has happened to them to any other creature except the one with whom they’ve swapped bodies (and only when others are out of earshot).
20. The ripples of your spellcraft are felt beyond your comprehension. Somewhere, some… thing… now knows your name. And it’s coming for you.