Spells with randomized effects per caster

So, a little while back I was reading Lizard's commentary on The Necromican (a rather gonzo and amateurish 1979 third-party D&D supplement). There are a lot of interesting spells in that odd book, but one really stood out to me.

Personal Energy Attack, Area Affected: Variable. Range: Variable. This spell is based on a personal power, differing in intensity and quality from character to character. This power gives the mage an offensive capability which increases with his level. Once the spell is taken, determine the characteristics of the power on the table below. (Roll for each characteristic separately.)

	Damage Per User's Level	Color	Shape
1	Nothing	Black	Bolt 10x30'
2-5	1	Red	Cone 20x10'
6-15	1 - 3	Orange	Beam 120' long
16-35	1 - 4	Yellow	Bolt 10x60'
36-65	1 - 6	Green	Cone 40x20
66-85	1 - 8	Blue	Beam 240' long
86-95	1 - 10	Purple	Bolt 10x120'
96-99	1 - 12	White	Cone 80x40'
00	1 - 20	Colorless	Beam 480' long

Yeah, so every caster who learns this spell rolls up their own unique version, suggesting that it's a weaponization of some kind of internal, immutable quality. And I love that!

There are some obvious issues with these specific mechanics, of course. The fact that the spell can turn out to be entirely useless (with that "Nothing" result) is pretty harsh, and the possibility of doing 1d20 damage per caster level in a massive cone is pretty nuts. The spread of potential here is wild. I sort of admire this ethos of throwing balance to the wind, but I'm not sure I can embrace it to such a degree.

Also, we could make the possibilities way more interesting! The spell table could include different damage types, more range/shape options, rider effects, other cosmetic traits, and maybe even drawbacks. The way I see it, the more factors we randomize, the more likely the results are to fall into the middle of a bell curve of utility.

Anyway, the broader concept of spells that are different for each user could be fun. I believe Dungeon Crawl Classics does something like this for all of its spells—that game is a paradise of random tables—via its "Mercurial Magic" rule. I'm also fairly sure I saw a spell or effect somewhere that turned the user into a random animal, with each individual getting the same form each time.

Transformations really do seem like an especially appropriate place to use this idea, suggesting things like totem animals, physical manifestations of higher selves, etc. Variable elements might also fit well.

The big question, though, is if multiple randomized spells should turn out to line up with each other. That is, if it turns out that one wizard's personalized energy blast spell manifests as a torrent of golden fire, should their apotheosis transformation spell also feature golden fire? I don't think it's necessary that this be the case. After all, the same seed number will generate completely unrelated results in one procedural generation engine vs. another. However, I think it would be more satisfying to connect the results, as if each such spell revealed another facet of an underlying truth about the caster!

Anyway. Just for kicks, I'll try reworking the personal energy attack spell.

Personal Energy Attack

Level 2 Evocation

Casting Time: Action (unless otherwise specified)
Range: Special
Components: V, S
Duration: Instantaneous (unless otherwise specified)

No two casters express this spell the same way. Every character who learns personal energy attack randomly rolls for the aesthetic and mechanical traits of their own version of the spell.

Once you've learned personal energy attack, you always have it prepared. In a spell-slot system, you can always spend a slot of level 2 or higher to cast it. In a spell memorization system, you can expend a memorized spell of level 2 or higher to cast this one.

Casting this spell leaves a magical imprint on its targets and the places where it's cast. Someone using detect magic or similar abilities can identify you as the caster.

1d12	Color
1	Black
2	Red
3	Orange
4	Yellow
5	Green
6	Cyan
7	Blue
8	Violet
9	White
10–12	Roll twice

1d10	Aesthetic
1	Boiling and surging
2	Complex filigrees, seemingly ornate
3	Gauzy and diffuse, possibly cloud-like
4	Glittering, sizzling motes and sparks
5	Heavy, blocky, angular
6	Simple, possibly geometric
7	Sparkling and crackling, furious
8	Subtle, a mere beam of colored light
9	Traceries of thin, bright lines
10	Twisting, billowing, organic, tentacular

1d20	Range
1	Touch Make an unarmed melee attack (using your spellcasting ability for the roll) against a single target to inflict the spell's damage on it.
2–3	Aura (radius: 1d4 × 5') All creatures and significant objects near you suffer the spell's damage (including your allies, but not yourself or your possessions), taking half damage on a successful saving throw.
4–6	Weapon (duration: 1d4 rounds) The spell manifests as a melee weapon in your hand. You're proficient with it, and attack with it using your spellcasting ability. On a successful attack, it delivers the spell's damage. You can use it repeatedly in melee as long as its duration lasts, or you can throw it like a dagger (regardless of its form) to deliver its damage at a distance, which will end the spell.
7–13	Single-target ray (range: 2d20 × 5') Make a ranged attack against a single target using your spellcasting ability to inflict the spell's damage on it.
14–16	Single-target auto-hit (range: 2d8 × 5') A single target you can see suffers the spell's damage.
17–18	Line (length 2d10 × 5', width 5') Creatures and significant objects in the area suffer the spell's damage, taking half damage on a successful saving throw.
19	Sphere (radius 1d6 × 5', range 2d12 × 5') Creatures and significant objects in the area suffer the spell's damage, taking half damage on a successful saving throw.
20	Cone (2d6 × 5') Creatures and significant objects in the area suffer the spell's damage, taking half damage on a successful saving throw.

1d20	Damage Type
1–2	Impact
3–4	Puncture
5–6	Slash
7–9	Cold
10–12	Corrosion
13–15	Electricity
16–18	Heat
19–20	Multi-type, roll twice

1d10	Damage
1–2	1d4 per level
3–6	1d6 per level
7–9	1d8 per level
10	1d10 per level

1d20	Quirk
1	Connection You become bonded with anyone who survives being injured by this spell. You know what direction they're in and when they're immediately present, but you can't distinguish one such being from another this way. They know the same about you.
2	Disorientation When you cast this, you and everyone adjacent to you suffer the effects of the confusion spell until the end of your next turn.
3	Dramatic Extremely loud and bright, noticeable from further away than other spells. Might trigger an encounter check.
4	Dual nature This spell can be cast in two different forms. Roll up new traits for its other mode. This probably means there's something unusual about you.
5	Ethereal The spell can harm intangible creatures. It can't harm tangible creatures.
6	Hands-free Requires no somatic components. Emanates from your eyes / mouth / general face area.
7	Hungry Each casting burns a day's worth of nutrients. Cast it after eating, and you'll want another meal. Cast it again, and it's like you've gone a day without food. And so on.
8	Inquisitive When you kill a living creature with this spell, you absorb one random memory from their brain.
9	Necromantic Living creatures killed by this spell (and whose bodies aren't destroyed) have an HD-in-20 chance to rise as feral undead in 1d6 days.
10	Physical traces When cast, leaves greasy, powdery residue of the spell's generated color on both you and your surroundings.
11	Reflexive When you take damage, save or cast this spell on your next turn. You automatically target the source of the damage if possible. Otherwise, aim the spell freely.
12	Reliable Not expended if it fails to do damage to anyone or anything. ("Anyone or anything" means creatures—including the caster and their allies—as well as objects of any importance.)
13	Relic This spell will outlive you. When you die, it will emerge from your body in the form of a thematically appropriate object. Mechanically, it'll be a wand that casts this spell (specifically your version) and has as many charges as you had levels.
14	Repulsion Creatures and unsecured objects within 5' get pushed 10' away from you. Creatures are also likely to trip and end up prone (probably getting a saving throw or something).
15	Rooted You can't move or be moved from your current position until the end of your next turn.
16	Self-harming Inflicts 1 HP per level of its damage type on the caster.
17	Set-up time Takes 2 rounds to cast.
18	Skybound This spell can only be cast under open sky.
19	Terror NPCs who see you cast this spell check morale (or save to avoid a fear effect). This goes for allied NPCs, too.
20	Unstable Every time you gain a level, reroll this spell's other traits. This also probably means something about you.

Closing comments

Admittedly, I didn't really write up a complete, play-ready spell here. My mechanics are deliberately edition-loose. The spell's "per level" damage could be interpreted according to the caster's level or according to the spell slot expended. I think its overall power is a little more predictable than the Necromican version, but it's definitely wild as hell, so I wouldn't make this available like a normal spell. It'd definitely have to be something a PC might pick up in the course of an adventure, on par with a magic item.

Oh, and you might notice I used the damage types from my previous post here. I actually started writing this article first, then realized I needed to do the damage types one to lay the groundwork.