Deepspawn
Traits
Amorphous. It can squeeze through a gap as narrow as 1 foot wide without squeezing penalties.
Regeneration. It regains 10 HP at the start of its turn. If it took Fire or Radiant damage, this feature doesn't function until the end of its next turn. If it has 0 HP and this feature doesn't trigger, it dies.
Spawn Memory. The Deepspawn can produce a copy of any creature it has eaten. The creature must be CR 5 or lower, and the Deepspawn must have consumed it within the last 30 days.
Campaign note: copies produced by the Deepspawn are exact duplicates of the original — but absolutely loyal to the Deepspawn. If a Deepspawn feeds for weeks, it can populate an Underdark region entirely on its own. This is a threat at the campaign level, not the stat block level.
Actions
Multiattack. It makes three Tentacle attacks. It can replace one of them with Engulf.
Tentacle. Melee Attack Roll: +9, reach 15 ft. Hit: 14 (2d8 + 5) Bludgeoning damage, and if the target is Large or smaller, it becomes Grappled (escape DC 17). The Deepspawn can hold three creatures Grappled at once.
Engulf. The Deepspawn swallows a Grappled creature it is holding. The target makes a DC 18 Strength save.
- Failure: The target is swallowed. A swallowed creature is Blinded and Restrained, has Total Cover against attacks from outside, and takes 21 (6d6) Acid damage at the start of the Deepspawn's turn.
- Success: The target is freed from being Grappled.
A swallowed creature can spend an action to try to escape with a DC 18 Strength (Athletics) check. When the Deepspawn dies, all swallowed creatures are released and fall Prone.
The Deepspawn can hold two creatures swallowed at once.
Birth Spawn (3/Day). Using Spawn Memory, the Deepspawn produces a creature. The produced creature appears within 10 feet of the Deepspawn, acts immediately after the Deepspawn's Initiative, and is absolutely loyal to it.
Limit: the Deepspawn can keep at most three spawn alive at once. The total CR of produced creatures can't exceed 8.
Reactions
Absorb Spawn. When a spawn within 30 feet of the Deepspawn is killed, the Deepspawn regains 20 (6d6) HP.
How to Use
The Deepspawn is both a boss and a campaign threat. Don't confuse the two.
In combat: it's a battle of action economy. The Deepspawn's 3 attacks plus 3 spawn erase the party's edge in numbers. Absorb Spawn is critical: if the party kills the spawn, the Deepspawn heals. This is a trap — the correct tactic is to ignore the spawn and focus on the Deepspawn.
Regeneration's counter is Fire/Radiant — the party has to find this. A Cleric/Paladin shines in this fight.
At campaign scale: make the Deepspawn a region's source. The party keeps encountering the same creatures again and again — always the same type, always the same tactics. Then they discover: they all come from one thing. This becomes an investigation arc.
Balance Note — deviation from the original
The original problem: the old Deepspawn could "birth more than one monster per day." In 5e this becomes an infinite XP machine — the party camps out and farms the Deepspawn.
My fixes:
- Birth Spawn 3/Day and max 3 spawn alive at once. Not unlimited.
- Total CR cap of 8 — the Deepspawn can't birth three CR 5 monsters; the math doesn't work.
- Absorb Spawn punishes killing spawn — so spawn aren't an XP source, they're an obstacle.
- Reproduction happens at the campaign level, not the stat block. The DM controls it narratively.
Encounter: for a 4-person Lv11 party, a single Deepspawn = 7,200 XP plus spawn. Budget (Medium) 4,100×4 = 16,400. With spawn, Medium–High. Excellent as a solo boss.
Mass Encounter Reference
| CR | Creature | XP | Recommended Party | Solo Difficulty (4 people) |
|---|---|---|---|---|
| 1/2 | Gibberling | 100 | Lv 1–3 | Use in a swarm (6–12 of them) |
| 1 | Carbuncle | 200 | Lv 1–4 | Social encounter — not for combat |
| 2 | Sheet Phantom | 450 | Lv 2–4 | Use 2–3 |
| 3 | Wolf-in-Sheep's-Clothing | 700 | Lv 3–5 | Solo + terrain advantage |
| 4 | Disenchanter | 1,100 | Lv 4–6 | Use as support |
| 4 | Adherer | 1,100 | Lv 4–6 | Solo, with an ambush |
| 5 | Flail Snail | 1,800 | Lv 5–7 | Solo or a pair |
| 5 | Thought Eater | 1,800 | Lv 5–8 | Solo, hit-and-run |
| 6 | Sussurus | 2,300 | Lv 6–8 | Location hazard |
| 6 | Death's Head Tree | 2,300 | Lv 6–8 | Solo + horror theme |
| 8 | Aurumvorax | 3,900 | Lv 7–10 | Mini-boss |
| 11 | Deepspawn | 7,200 | Lv 10–13 | Boss |
Design Principles — what I changed and why
These creatures from older editions carry the design philosophy of their era: punish the player, destroy their resources, erase their character from the game. 5e deliberately abandoned that philosophy.
I applied three rules in every adaptation:
1. Temporary dampening instead of permanent loss. The Disenchanter's "permanently erase your +1," the Aurumvorax's "swallow your weapon" — these generate anger, not tension. I made all of them recoverable with a Short/Long Rest. Permanent loss is still possible, but very hard, and the player has a chance to intervene.
2. Symmetric threat instead of asymmetric punishment. The Thought Eater only hit casters, the Adherer only hit martials. I rewrote both to affect everyone. Nobody says "this creature doesn't touch me at all" or "I'm completely out of the game."
3. Every creature has a clear way out. Adherer → Fire. Sussurus → go Deafened. Death's Head Tree → Fire / range. Deepspawn → Fire/Radiant. Aurumvorax → magic weapon. Sheet Phantom → sunlight.
This turns a "punishing monster" into a "puzzle monster." The party isn't helpless — they just need to find the right tool. And when they find it, that moment feels earned.
License note: The stat blocks in this file are original works; none have been copied from any older edition's text. The rule terms and mechanics used are based on SRD 5.2 (Wizards of the Coast LLC, CC-BY-4.0). This work includes material from the System Reference Document 5.2 ("SRD 5.2") by Wizards of the Coast LLC, available at https://www.dndbeyond.com/srd. The SRD 5.2 is licensed under the Creative Commons Attribution 4.0 International License, available at https://creativecommons.org/licenses/by/4.0/legalcode.