Star-Nosed Diopsid

Large aberration, lawful evil

Armor Class 16 (natural armor)
Hit Points 153 (18d10 + 54)
Speed 30 ft., burrow 15 ft., fly 30 ft.

19 (+4) 14 (+2) 17 (+3) 17 (+3) 16 (+3) 15 (+2)

Saving Throws Con +7, Int +7, Wis +7
Skills Perception +7, Stealth +6
Damage Resistances bludgeoning, piercing, and slashing from nonmagical attacks
Senses darkvision 60 ft., tremorsense 60 ft., passive Perception 17
Languages Deep Speech, Undercommon, telepathy 100 ft. (300 ft. with its own kind)
Challenge 9 (5,000 XP)
Proficiency Bonus +4


  • Mutagenic Venom. The diopsid produces a potent poison that envenoms the Humanoid victim and slowly transforms it into a new diopsid. While envenomed, a Humanoid treats all diopsid as if it were charmed by them. Every 24 hours that elapse, the envenomed creature must make a DC 16 Constitution saving throw, reducing its hp maximum by 5 (2d4) on a failure. This reduction lasts until the creature finishes a long rest after the venom is removed. The creature dies if this effect reduces its hp maximum to 0. A Humanoid that dies from this effect undergoes a horrific transformation, becoming a new diopsid and losing all memory of its former life. This potent poison remains within the creature’s body until removed by the greater restoration spell or similar magic.


  • Multiattack. The diopsid makes one Stinger attack and two Tentacle attacks.
  • Stinger. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 26 (4d10 + 4) piercing damage. If the target is a Humanoid, it must succeed on a DC 16 Constitution saving throw or succumb to the diopsid’s venom (see the Mutagenic Venom trait).
  • Tentacle. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 17 (3d8 + 4) bludgeoning damage. The target is grappled (escape DC 16) if it is a Large or smaller creature and the diopsid doesn’t have two other creatures grappled.
  • Share Senses. While within 300 feet of an envenomed Humanoid, the diopsid see through the target’s eyes and hear what the target hears until the start of its next turn, gaining the benefits of any special senses the target has. On subsequent turns, the diopsid can use a bonus action to extend the duration of this effect until the start of its next turn.
  • Control Envenomed (3/Day). While within 300 feet of an envenomed Humanoid, the diopsid can telepathically suggest a course of activity to it. The Humanoid must succeed on a DC 16 Wisdom saving throw or pursue the course of activity suggested to it. On a success, the Humanoid takes 11 (2d10) psychic damage and has disadvantage the next time it makes this saving throw. This effect works like the suggestion spell, and the Humanoid is unaware of the diopsid’s influence.


This horse-sized, insectoid creature has long eyestalks sticking out to the sides of its head. The starburst tentacles at the end of its proboscis move rhythmically as it scuttles forward.

Diopsids are highly intelligent, bug-like aberrations. They are semi-social and dig their small communal homes in intricate tunnel complexes in forests and grasslands not far from civilized lands. They hunt as ambush predators, burying themselves in the loose soil to latch onto unsuspecting prey. They also reproduce this way; captured humanoids are injected with a magical venom that eventually transforms the envenomed into another diopsid. In the meantime, those infected live their short lives as the eyes and ears of these strange creatures.

Students of Humanoid Nature. Diopsids often co-opt the senses of envenomed victims to observe humanoid culture and interactions. A diopsid will shadow the humanoid, close enough to remain in telepathic contact, and observe what goes on around it. Useful information is taken back and shared with the colony, adding to their collective knowledge.

Section 15: Copyright Notice

Tome of Beasts 3 © 2022 Open Design LLC; Authors: Eytan Bernstein, Celeste Conowitch, Benjamin L. Eastman, Robert Fairbanks, Scott Gable, Basheer Ghouse, Richard Green, Jeremy Hochhalter, Jeff Lee, Christopher Lockey, Sarah Madsen, Ben Mcfarland, Jonathan Miley, Kelly Pawlik, Sebastian Rombach, Chelsea Steverson, Brian Suskind, Mike Welham

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