Purple Worms have been in D&D since at least the days of BECMI, and are likely inspired by the sand worms of Frank Herbert’s Dune. They’re in both the Monster Manual and Monster Vault.

The Lore

Believe it or not, purple worms were not created by some drug-addled wizard or vengeful primordial. They’re entirely natural creatures, just like cats and dogs. Or drakes. Or behemoths. Or bullettes. Yeah, the world of D&D is kind of a dangerous place.

Large enough to swallow a giant whole, purple worms burrow through the Underdark and through rocky and mountainous terrain on the surface. They’re not always hungry, but their feeding strategy is gorging themselves about once a week so the end result is more or less the same. They’re such efficient tunnelers that you can’t tell they’re coming until they’re almost directly underneath you. They also have a knack for showing up precisely when people think things can’t get any worse. Large Underdark settlements are always protected by a perimeter of anti-worm wards, and when these settlements war with each other sabotaging those wards is a popular move.

Unlike the Dune sand worms, purple worms can burrow through solid rock just fine, and in addition to their cavernous maws some have a venomous stinger on the tip of their tails. They dig by eating the rock or soil and quickly excreting it, though stuff like refined metal, precious ores and gems have a tendency to stick in the worm’s gut for longer periods. So if you manage to kill one, its gut may contain treasure!

Purple worm tunnels are very large and permanent, and they don’t reuse them. An area rich in food might have several purple worms hunting it, and will end up looking like a labyrinth. Worm tunnels tend to become important natural roads in the Underdark, and it’s not uncommon for smaller creatures to move into them right after the worm passes them by. Instant ecosystem!

These beasts are impossible to tame, but people keep trying to use magic to control them. Drow and illithids can’t resist their potential as a weapon, and dwarves can’t resist their potential as a construction tool. I mean, a purple worm could likely have dug the tunnel under the English Channel in a fraction of the time the real-world construction crew took.

Of course, it’s pretty much inevitable that these spells will wear off at the worst possible time, leading to disaster. After digging the tunnel, that same purple worm would have likely delivered a much quicker and less painful Brexit by eating Britain.

The Numbers (Monster Manual)

Purple Worms are Natural Beasts with the Blind keyword. They have both tremorsense 20 and blindsight 10, plus a respectable burrow speed with Tunneling. We have two stat blocks here.

Purple Worm

The basic model is Huge, and a Level 16 Solo Soldier with 780 HP. As a blind creature, it’s immune to gaze attacks, and also immune to illusions. It crawls at speed 6, and burrows at speed 3.

The worm’s basic attack is a Reach 3 Bite that, unlike most basic attacks in the book, targets Reflex. No amount of armor is going to protect you from it! A hit does damage and grabs the target (Athletics DC 34 or Acrobatics DC 30 to escape).

Once the worm has grabbed a target, it can “worry” it with its Clamping Jaws, which has the same accuracy vs. Reflex and damage as a basic bite but does half damage on a miss.

It can also try to Swallow them. This targets the Fortitude of the victim. On a hit, the target gets swallowed and is now inside the purple worm. The victim is considered dazed and restrained, and only has line of sight and effect to the worm. Also, no one has line of sight or effect to the victim.

While swallowed, the victim can only make basic attacks, and takes 10 physical and 10 acid damage at the start of the worm’s turns. The only good news here is that the worm’s AC is like 8 points lower from the inside. The only way to escape is to kill the worm, which causes the victim to be regurgitated.

The worm can’t bite other people while it has a target grabbed in its jaws, but it can fight normally after swallowing. There’s no mention of how many victims fit in its gullet. “One” is the merciful answer, but “1 Large or 2 Medium or 4 Small” is traditional.

Elder Purple Worm

Elder Purple Worms have grown to size Gargantuan (the largest possible under the rules). They’re large enough to swallow titans! Elders are Level 24 Solo Soldiers with 1145 HP and the same immunities as the younger specimen. Their land speed is 8 and their burrowing speed 4.

The elder’s attacks are exactly the same as those of the basic worm, with bigger numbers. Their AC is 7 points lower from the inside, and their digestive damage is 20 physical and 20 acid per turn. Again there’s no mention of how many creatures fit in the worm’s gullet. The traditional answer would be “1 Huge or 2 Large or 4 Medium or 8 Small”, but it might be a tad unfair to allow it to swallow the whole party.

The Numbers (Monster Vault)

Purple worms in the Vault are fairly different, and generally more adequate for use as solo encounters. We also get two stat blocks, and both are Huge Natural Beasts (blind).

Adult Purple Worm

Adult Purple Worms are Level 14 Solo Brutes with 560 HP. Not sure if I mentioned this before, but the new monster math also gives solos less HP. Their tremorsense and blindsight are both range 10, and they both crawl and burrow at speed 6.

As a MV Solo, this worm has some traits that help it stand up to a paragon party: Ponderous allows it to take immediate actions while stunned, dazed, or dominated; and Bloodied Frenzy allows it to take an extra minor action in its turn while bloodied.

The basic Reach 3 Bite now targets AC, and has no riders to its considerable damage. All the gizzard gimmicks are now packed into the Devour Whole attack (Melee 3 vs. Fortitude). A hit here does similar damage to a bite and swallows the target.

Being swallowed here is a little less nightmarish than for the MM version. The restrictions on line of sight and effect still apply, and the victim is off the board and so obviously can’t move around. However, they are no longer dazed or restrained, and can use any of their attacks against the worm. They can even try to crawl out of its gullet as if escaping from a grab, rolling against a lenient DC of 21.

On the other hand, the worm’s defenses are the same from the inside now. Swallowed victims take 30 acid damage at the end of their own turns, and any close or area attacks used from inside the worm also target all other creatures swallowed by it. While we still get no word on what’s the limit for those, we do have explicit confirmation that there can be more than one. So you can choose between the traditional answer and “no limit”!

This worm also has a lot of other options to bring pain to the party, all of them minor actions. Fling (Melee 3 vs. Fortitude) deals damage and slides the target 4 squares; Regurgitate spits out a swallowed victim, making it appear within 4 squares of the worm and take a chunk of automatic damage; and the Poison Stinger (Melee 3 vs. Fortitude) mentioned in the Lore section does a bit of physical damage and 15 ongoing poison damage (save ends). With Bloodied Frenzy active, it can do all three and still swallow someone.

You also have Thrash, a reaction that triggers whenever an attack hits the worm. It’s a Melee 3 attack vs. Reflex, targeting one or two creatures, doing the same damage as the bite and pushing them up to 6 squares. This is why it has Ponderous!

Purple Worm Tunneler

This specimen is quite a bit faster, and likely the one you want to use for your Eurotunnel/Brexit combo. It’s a Level 19 Solo Skirmisher with 728 HP. Its land and burrow speeds are 8.

The tunneler has the same Ponderous and Bloodied Frenzy traits as the basic model. Its Bite does damage and allows it to shift half its speed on a hit. Devour Whole also works the same, with an escape DC of 24.

As a move action, the tunneler can Barrel Through its foes, shifting its speed and making an attack against the Reflex of every enemy it passes adjacent to. A hit here does a bit of damage and pushes the target 2 squares.

The tunneler also has a bigger stinger, since its minor-action attack is Stinger Impalement (Melee 3 vs. AC). This does more physical damage than the basic worm’s stinger, slides the target 4 squares, and deals 10 ongoing poison damage (save ends). There’s no limit to the number of times per round it may do this, so you’re looking at up to three impalement attacks plus a devouring when the worm is bloodied.

Finally, it also has Thrash, which works the same way with bigger numbers.

Sample Encounters and Final Impressions

The Monster Manual has a level 18 sample encounter: 1 purple worm, and 2 savage minotaurs.

Purple worms don’t cooperate with anyone, of course, but they’ll often be attracted by fights against other monsters and try to eat everyone present, just like Bullettes but on a bigger scale. In other words, purple worms are just the thing to use on a party who’s all happy that they’ve outgrown bullettes.

I like purple worms! I don’t think they’re exclusive content, but they’re still a very D&D kind of monster. In previous editions I kinda felt they suffered from the same problem as dragons, looking so powerful that people rarely put them in their games. Here, I have a better handle of when they’re appropriate.