I started to put together some Star Frontier monsters that can be used for a D&D 5th edition – Star Frontiers Campaign. I stated first with a creature that you should find interesting.  It is really big and scary, 65 feet long, and is able to hide and sneak attack the player characters.  It was the Slither, so I tweaked it a bit, but kept the same flavor. I first started by using the Purple Worm layout, but soon found ideas from several other monsters in the Monster Manual.  I stayed focused on the origional listing of Slither’s abilities: 1. surprise, 2. chemical burn touch, 3. tentacle attack, 4. a bite attack, 5. tentacle grapple. and 6. multi-creature attack, and added some legendary actions to the creature. So here is the Slither:



Slithers are Sathar attack monsters. The Sathar, in their efforts to destroy peaceful worlds, have genetically altered a number of creatures into “monsters” which they set free on various worlds. Slithers and other Sathar attack monsters can be encountered on many different planets.

A slither is 65 feet long and 6 feet wide. It resembles a giant-sized cross between a worm and a centipede. It is part plant and part animal; plants grow from its back, providing camouflage and some nourishment from photosynthesis. It can only see moving objects, but can sense salt and water. One often lurks near pools of water or salt licks, waiting for prey.

When lying still, a Slither is often mistaken for a mound of plants, allowing it to attack with surprise. Its gnashing, grinding mandibles are surrounded by 2-meter-long tentacles. Slithers also secrete an oily fluid that causes burns on touch. They attack by lashing out with their tentacles, by biting with their jaws and by coiling around prey and burning it with their secretions. They must re-coil and make a new attack roll each turn to coil about prey. A slither can attack two creatures on the same turn, one with its tentacles and bite and the other by coiling around it. This makes them very deadly in combat.


Gargantuan monstrosity, lawful evil

Armor Class 19 (natural armor)
Hit Points 245 (14d20 + 98)
Speed 30 ft., swim 45 ft.
20 (+5) 10 (+0) 24 (+7) 8 (-1) 8 (-1) 4 (-3)
Skills Perception +4, Stealth +10
Damage Immunities lightning, fire, poison, acid; bludgeon, piercing, and slashing from nonmagical weapons
Condition Immunities charmed, blinded, frightened, paralyzed, poisoned, prone.
Senses blindsight 60 feet, Passive Perception 14
Languages Sathar
Challenge 15 ( 13,000 XP)
  • False Appearance. When the slither remains motionless and coiled, it looks like a large hill with plants on top.
  • Acid Touch.  Any creature that hits with a melee attack, or touches the slither will suffer a chemical burn from a splash of it’s secretions, and any other creature that is within 5 feet of it will suffer 11 (2d10) acid damage.


  • Multiattack. The slither uses its frightful presence and then makes three attacks: one with its bite, and two with its tentacle constrict. 
  • Bite. Melee Weapon Attack +10 to hit, reach 5 ft., one target. Hit: 80 (5d10 + 25) piercing damage.
  • Tentacle Constrict. Melee Weapon Attack +10 to hit, reach 10 ft., one target each tentacle. Hit: 96 (6d10+30) bludgeoning damage, and the target is grappled (escape DC 18). Until this grapple ends, the creature is restrained, and the slither can’t constrict another creature with that tentacle. The slither has advantage on bite attacks against the constricted creature.
  • Frightful Presence. Each creature of the slither’s choice that is within 120 feet and aware of it must succeed on a DC 16 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If the a creature’s saving throw is successful or the effect end for it, the creature is immune to the slither’s Frightful Presence for the next 24 hours.
  • Swallow. The slither makes one bite attack against a creature it is grappling. If the attack hits, the target takes the bite’s damage, the target is swallowed, and the grapple ends. While swallowed, the creature is blinded and restrained, it has total cover against attacks and other effects out side the slither, and it takes 56 (16d6) acid damage at the start of each of the slither’s turns. If the slither takes 60 damage. or more on a single turn from a creature inside it, the slither must succeed on a DC 20 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of the slither. If the slither dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 30 feet of movement, exiting prone.

Legendary Actions:

The slither can take 3 legendary actions, choosing from the options below. Only one legendary action option can be use at a time, and only at the end of another creature’s turn. The slither regains spent legendary actions at the start of its turn.

  • Attack. The slither makes one bite or constrict attack.
  • Eat. The slither makes a bite or swallow attack.
  • Coil. The slither can quickly recoil it’s body, and move up to it’s speed without provoking opportunity attacks, or reactions from other creatures.

The slither is very strong, but with a party of mid-level adventurers, they should be able to take it out fairly quickly.

Have fun!


Source reference material:



Star Frontiers: Part 1 | Part 2 | Part 3 | Part 4 | Part 5 | Part 6