Caustic Compendium

Once a beautifully crafted tome with a copper cover, the Caustic Compendium is now shrouded in a dark green, almost black, patina. The edges have corroded over time, perhaps from the experiments that led to the creation of the spells within. The cover features an intricate design of oozes and slimes, their long, tendril-like pseudopods intertwining with the curved borders. The book wreaks of sulfur, and its worn pages bear occasional burn marks and holes that pierce through multiple layers.

Inside, the compendium contains a number of unique and never-before-seen spells, accompanied by notes detailing their creation process and the failed experiments that eventually led to success. Drafts of the completed spells are included, with precise distances, components, and brainstormed names. Some pages are damaged beyond repair, hinting at spells or failed attempts that are lost to time. Additionally, there are notes on spells still in development, such as sourface, which purportedly turns a victim’s face inside out, but remains little more than an amusing idea.

Spells

Level	Spell	School	Conc.	Ritual	Class
1	Acid Rain	Evocation	Yes	No	Druid, Sorcerer, Wizard
2	Acrid Blood	Transmutation	No	No	Cleric, Druid
2	Corrosive Whip	Evocation	Yes	No	Druid, Sorcerer, Wizard
2	Summon Slime	Conjuration	Yes	No	Druid, Sorcerer, Warlock, Wizard
2	Viscous Bolt	Evocation	No	No	Sorcerer, Wizard
3	Wall of Acid	Evocation	Yes	No	Druid, Sorcerer, Wizard
4	Caustic Cube	Conjuration	Yes	No	Druid, Warlock, Wizard
5	Slimy Transformation	Transmutation	Yes	No	Druid, Sorcerer, Warlock, Wizard
6	Sulfuric Wind	Conjuration	No	No	Druid, Warlock, Wizard
7	Biting Tongue	Transmutation	Yes	No	Bard, Druid, Sorcerer, Wizard

Acid Rain

1st-Level Evocation
Casting Time: 1 action
Range: 90 feet
Components: V, S, M (a flask of powdered niter)
Duration: Concentration, up to 1 minute

A 10-foot-radius storm cloud floats in the air, dropping acid rain drops in a 30-foot-high cylinder centered on a point you can see within range.

When a creature enters the spell’s area for the first time on a turn or starts its turn there, it is drenched in acid droplets and it must make a Constitution saving throw. On a failed save, it takes 3d4 acid damage, or half as much damage on a successful one.

Objects within the area that aren’t being worn or carried take double damage from the acid droplets.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, increase the radius by 5 feet for each spell slot level above 2nd. The spell deals an additional 1d4 acid damage to creatures in the area for each spell slot level above 2nd.

Acrid Blood

2nd-Level Transmutation
Casting Time: 1 action
Range: Touch
Components: V, S, M (a preserved lemon peel)
Duration: 1 hour

You touch a willing creature. Until the spell ends, when the target is dealt damage by a creature within 5 feet of it, the creature takes 1d4 acid damage.

Additionally, when you cast the spell, you end one disease or the poisoned condition afflicting the target.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, you can target one additional creature for each slot level above 2nd.

Biting Tongue

7th-Level Transmutation
Casting Time: 1 action
Range: Self
Components: V, S
Duration: Concentration, up to 1 minute

Your tongue elongates and seeps acid. As a bonus action, you can make a melee spell attack against a Large or smaller creature within 60 feet of you. On a hit, the target takes 6d6 acid damage and has the grappled condition. You can only grapple one target at time with your tongue. While grappled in this way, the target takes 6d6 acid damage at the start of each of its turns.

A creature grappled by the tongue can use its action to make a Strength check against your spell save DC. If it succeeds, it is no longer grappled.

At Higher Levels. When you cast this spell using an 8th-level spell slot, you can target a Huge or smaller creature. When you cast this spell using a 9th-level spell slot, you can target a Gargantuan or smaller creature.

Caustic Cube

4th-Level Conjuration
Casting Time: 1 action
Range: 150 feet
Components: V, S, M (a cube of clear crystal)
Duration: Concentration, up to 1 minute

You conjure a 30-foot cube of semitransparent jelly at a point you can see within range. The jelly squeezes to fit into a smaller space and spreads around corners.

Creatures in the area when you cast the spell must make a Dexterity saving throw. On a successful save, the creature is pushed to the nearest unoccupied space outside the area. On a failed save, the creature has the restrained condition, it can’t breathe, and takes 4d6 acid damage at the start of its turn. Creatures inside the area can be seen but have total cover. A creature that enters the area suffers the consequences of a failed saving throw.

A creature restrained by the spell can try to escape by taking an action to make a Strength check against your spell save DC. On a success, the creature escapes and enters the nearest unoccupied space outside the spell’s area.

A creature outside the area can take an action to pull a creature or object within its reach out of the area. Doing so requires a successful Strength check against your spell save DC and the creature making the attempt takes 2d6 acid damage.

Creatures that aren’t completely enclosed within the area have advantage on saving throws against this spell and ability checks to escape.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, increase the size of the cube by 5 feet for each spell slot level above 3rd. The spell deals an additional 1d6 acid damage to creatures in the area for each spell slot level above 3rd.

Corrosive Whip

2nd-Level Evocation
Casting Time: 1 bonus action
Range: Self
Components: V, S, M (a twig from a citrus tree)
Duration: Concentration, up to 10 minutes

A whip dripping with a yellowish-green acid appears in your free hand. The magic whip lasts until the spell ends. It counts as a simple melee weapon with which you are proficient. It deals 4d4 acid damage on a hit and has the finesse and reach properties. Additionally, nonmagical armor worn by the target is partly dissolved and takes a permanent and cumulative -1 penalty to the AC it offers. The armor is destroyed if the penalty reduces its AC to 10.

If you let go of the whip, it disappears. As a bonus action, you can cause the whip to reappear in your hand.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, damage increases by 1d4 for each slot level above 2nd.

Slimy Transformation

5th-Level Transmutation
Casting Time: 1 bonus action
Range: Self
Components: V, S, M (a candle in the shape of an ooze worth at least 400 gp)
Duration: Concentration, up to 1 minute

Slime seeps from your pores transforming you, giving you slimy features. You gain the following benefits until the spell ends.

Slither. You can move through a space as narrow as 1 inch wide without squeezing and you can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Resilient. You gain 30 temporary hit points and you are immune to acid damage. If any of these temporary hit points remain when the spell ends, they are lost.

Acidic Burst. When you cast this spell, and as a bonus action on subsequent turns for the duration, you can create a whirlwind of acid in a 10-foot-radius sphere centered on you. Each creature in that area must make a Constitution saving throw, taking 4d6 acid damage on a failed save, or half as much damage on a successful one.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the temporary hit points increases by 20 for each slot level above 5th.

Sulfuric Wind

6th-Level Conjuration
Casting Time: 1 action
Range: Self (60-foot line)
Components: V, S, M (a vial of sulfur)
Duration: Instantaneous

A line of foul smelling wind 60 feet long and 30 feet wide blasts from you in a direction you choose. Each creature in the area must make a Constitution saving throw. On a failed save, a creature takes 6d8 acid damage, has the prone condition, and has the poisoned condition for 1 minute. On a successful save, a creature takes half a much damage only. A creature poisoned this way can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

The wind disperses gas or vapor, and it extinguishes candles, torches, and similar unprotected flames in the area. It causes protected flames, such as those of lanterns, to dance wildly and has a 50 percent chance to extinguish them.

At Higher Levels. When you cast this spell using a spell slot of 7th level or higher, the damage increases by 1d6 for each slot level above 6th.

Summon Slime

2nd-Level Conjuration
Casting Time: 1 action
Range: 90 feet
Components: V, S, M (chewed wax in a gold-inlaid bottle worth at least 200 gp)
Duration: Concentration, up to 1 hour

You call forth a slime spirit. It manifests in an unoccupied space that you can see within range. This corporeal form uses the Slime Spirit stat block. When you cast the spell, choose a slime quality: Corrosive, Oily, or Viscous. The creature resembles you but is made of slime with the chosen aspect, which determines certain traits in its stat block. The creature disappears when it drops to 0 hit points or when the spell ends.

The creature is an ally to you and your companions. In combat, the creature shares your initiative count, but it takes its turn immediately after yours. It obeys your verbal commands (no action required by you). If you don’t issue any, it takes the Dodge action and uses its move to avoid danger.

Slime Spirit

Medium Ooze

Armor Class 10 + the level of the spell (natural armor)

Hit Points 35 + 5 for each spell level above 2nd

Speed 30 ft., climb 30 ft. (Viscous only)

STR	DEX	CON	INT	WIS	CHA
16 (+3)	6 (-2)	18 (+4)	4 (-3)	14 (+2)	2 (-4)

Damage Resistances acid, cold, fire

Condition Immunities blinded, charmed, deafened, exhaustion, frightened, grappled (Oily only), prone

Senses blindsight 60 ft. (blind beyond this radius), passive Perception 12

Languages understands the languages you speak

Challenge –

Proficiency Bonus equals your bonus

Amorphous. The slime can move through a space as narrow as 1 inch wide without squeezing.

Spider Climb (Viscous Only). The slime can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Corrode Metal (Corrosive Only). Any nonmagical weapon made of metal that hits the slime corrodes. After dealing damage, the weapon takes a permanent and cumulative −1 penalty to damage rolls. If its penalty drops to −5, the weapon is destroyed. Nonmagical ammunition made of metal that hits the ooze is destroyed after dealing damage.

The slime can eat through 2-inch-thick, nonmagical metal in 1 round.

Actions

Multiattack. The slime makes a number of attacks equal to half this spell’s level (rounded down).

Caustic Pseudopod (Corrosive Only). Melee Weapon Attack: your spell attack modifier to hit, reach 5 ft., one target. Hit: 1d4 + 3 + the spell’s level acid damage, and if the target is wearing nonmagical metal armor, its armor is partly corroded and takes a permanent and cumulative −1 penalty to the AC it offers. The armor is destroyed if the penalty reduces its AC to 10.

Sticky Pseudopod (Viscous Only). Melee Weapon Attack: your spell attack modifier to hit, reach 5 ft., one target. Hit: 1d8 + 3 + the spell’s level acid damage, and if the target is Large or smaller, it has the grappled condition (escape DC is equal to your spell save DC).

Slippery Pseudopod (Oily Only). Melee Weapon Attack: your spell attack modifier to hit, reach 5 ft., one target. Hit: 1d4 + 3 + the spell’s level acid damage, and if the target is a Large or smaller creature, it must succeed on a Strength saving throw against your spell save DC or have the prone condition.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, use the higher level wherever the spell’s level appears in the stat block.

Wall of Acid

3rd-Level Evocation
Casting Time: 1 action
Range: 90 feet
Components: V, S, M (a vial of oil)
Duration: Concentration, up to 1 minute

You create a wall of bubbling acidic slime on a solid surface within range. You can make the wall up to 30 feet long, 20 feet high, and 1 foot thick, or a ringed wall up to 20 feet in diameter, 20 feet high, and 1 foot thick. The wall is opaque and lasts for the duration. A creature entering the wall’s space must succeed on a Strength saving throw or fall prone.

When the wall appears, each creature within its area must make a Dexterity saving throw. On a failed save, a creature takes 3d8 acid damage, or half as much damage on a successful save.

A creature that ends its turn within 5 feet of the wall takes 1d8 acid damage. A creature takes 3d8 acid damage when it enters the wall for the first time on a turn or ends its turn there.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d8 for each slot level above 3rd.

Viscous Bolt

2nd-Level Evocation
Casting Time: 1 action
Range: 90 feet
Components: V, S, M (a fish air bladder)
Duration: Instantaneous

A ball of acid forms in your hand that you launch at a point you can see within range that explodes in a 10-foot-radius sphere. Each creature in the area must make a Dexterity saving throw. On a failed save, a creature takes 4d4 acid damage and at the beginning of each of its turns, it takes 1d4 acid damage as the acid adheres to it. On a successful save, a creature takes half as much initial damage only.

As an action, a creature within reach of adhered acid can remove it (no check required).

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, damage increases by 1d4 (initial and repetitive damage) for every two slot levels above 2nd.