| Hit Dice: | 18d8+90 (171 hp) |
| Initiative: | +6 |
| Speed: | 20 ft. (4 squares), climb 10 ft. |
| Armor Class: | 18 (−2 size, +2 Dex, +8 natural), touch 10, flat-footed 16 |
| Base Attack/Grapple: | +13/+30 |
| Attack: | Tentacle slap +20 melee (1d8+9) |
| Full Attack: | 2 tentacle slaps +20 melee (1d8+9) |
| Space/Reach: | 15 ft./10 ft. |
| Special Attacks: | Engulf, psionics, suffocating constriction 1d8+10 |
| Special Qualities: | Camouflage, darkvision 60 ft., tremorsense 60 ft. |
| Saves: | Fort +13, Ref +10, Will +12 |
| Abilities: | Str 28, Dex 15, Con 20, Int 11, Wis 13, Cha 16 |
| Skills: | Climb +17, Hide +10, Listen +11, Move Silently +12, Spot +11; racial bonuses |
| Feats: | Alertness, Great Fortitude, Improved Initiative, Lightning Reflexes, Power Attack, Skill Focus (Hide), Skill Focus (Move Silently) |
| Environment: | Any underground |
| Organization: | Solitary or pair |
| Challenge Rating: | 15 |
| Treasure: | None |
| Alignment: | Always neutral evil |
| Advancement: | 19–32 (Huge); 33–54 (Gargantuan) ♊ |
| Level Adjustment: | — |
In the depths of the earth, tunnel terrors (also known as rockworms) carve out treacherous mazes and pitfalls that misdirect unsuspecting wanderers into their great maws. These bizarre predators are distantly related to delvers.
A tunnel terror looks like a gigantic stony worm that has been hollowed out, leaving only a thick, tubular hide. It has two flat tentacles, each positioned at one end of its body. When at rest, these tentacles are outstretched and blend in with a tunnel ceiling or wall. Tunnel terrors have no mouth, eyes, or ears. They use psionic abilities and tremorsense to interact with their environment.
Tunnel terrors keep their lairs under constant surveillance with their divination abilities. When prey is near, they use psionics to strengthen their combat abilities, and then they lie in wait for the perfect moment to strike.
Creatures stepping into a tunnel terror’s space suddenly find themselves engulfed as the beast contracts to wrap around its prey. Wrapped creatures are ground into paste from the violent constriction and then absorbed into the terror’s wall lining. While digesting a meal, a tunnel terror keeps other foes at bay with tentacle attacks, usually triggering traps that bury or seal off its enemies.
Engulf (Ex): A tunnel terror can engulf one Large or smaller foe that has stepped into its body by making a successful grapple attempt against its foe. This move does not provoke an attack of opportunity. Engulfed victims are entangled and automatically take damage from suffocating constriction. If the tunnel terror gets a hold, it is free to use its tentacles to strike at other targets while it constricts. Attacks made on an engulfing tunnel terror deal half their damage to the monster and half to the trapped victim.
Psionics (Sp): At will—arcane eye, bull’s strength, cat’s grace, bear’s endurance, prying eyes, stone shape, telekinesis, wall of stone. Caster level 12th; save DC 13 + spell level.
Suffocating Constriction (Ex): An engulfed creature takes 1d8+13 points of bludgeoning damage, has no air to breathe, and begins to suffocate.
Camouflage (Su): Since a tunnel terror looks like a part of the tunnel when at rest, it takes a successful Spot check (DC 20) to notice it before it attacks. Dwarves can use stonecunning to notice a tunnel terror.
Skills: Tunnel terrors have a +8 racial bonus on Climb checks and can always choose to take 10 on Climb checks, even if rushed or threatened.
Source: Fiend Folio, page 179. Changes applied as per the D&D® v.3.5 Accessory Update.