Rules edition: This article uses the 2014 Monster Manual Purple Worm stat block. Do not mix its actions and numbers with the revised Purple Worm stat block in the current Monster Manual; choose one version for your game.
Purple can suggest the uncanny, the regal, or the dangerous, depending on how you use it. Treat color and atmosphere as description, then use the selected creature’s actual rules for its abilities. Purple dragons, gems, and aberrations do not all share one color-based mechanic.
Using purple as a visual cue
A violet glow can mark an unfamiliar place, a noble house, or an influence that players have not encountered before. Establish what the color means in your setting and use it consistently. If the color signals a mechanical property—such as resistance or a spell effect—state that as a DM-created feature rather than implying all purple creatures share it.
The same approach works for portals, relics, and corrupted landscapes. A hue can foreshadow danger without revealing the exact creature or effect. Give players other clues, too, so color is a story signal rather than a hidden rules test.
The 2014 Purple Worm
The 2014 Purple Worm is a CR 15 Gargantuan monster with AC 18, 247 hit points, a 50-foot walking speed, and a 30-foot burrowing speed. It has tremorsense out to 60 feet. Its 2014 Multiattack makes one Bite and one Tail Stinger attack.
Bite: The attack deals 3d8 + 9 piercing damage on a hit. If the target is Large or smaller, it must make a DC 19 Dexterity saving throw or be swallowed. A swallowed creature is blinded and restrained, has total cover against effects from outside the worm, and takes 6d6 acid damage at the start of each of the worm’s turns.
If a swallowed creature deals 30 damage or more to the worm from inside it during one turn, the worm must succeed on a DC 21 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures. They fall prone in spaces within 10 feet of it. If the worm dies, a swallowed creature can use 20 feet of movement to escape from the corpse, exiting prone. This is not an attack against an interior AC and does not create a hole that closes as a bonus action.
Tail Stinger: On a hit, it deals 3d6 + 9 piercing damage. The target must also make a DC 19 Constitution saving throw, taking 12d6 poison damage on a failed save or half as much on a successful one.
Running the encounter
Tremorsense detects and pinpoints the source of vibrations within its range. The silence spell prevents sound in its area; it does not erase movement’s physical vibrations. Do not use silence as a guaranteed way to hide a creature moving across the ground from the 2014 Purple Worm’s tremorsense.
Describe the tunnel, disturbed stone, or shifting ground to give the party clues. The monster’s rules already make it dangerous; use terrain and foreshadowing to give players choices about distance, escape routes, and whether to engage.
