This creature looks like a long, thin transparent protoplasm, almost snake-like in form.
Slithering Tracker CR 3
Speed 10 ft., climb 10 ft.
Melee slam +6 (1d4+3 plus paralysis)
Special Attacks engulf (paralysis and plasma drain), paralysis (1d4 hours, DC 17, also when struck by unarmed attacks or natural weapons), plasma drain
Str 14, Dex 10, Con 21, Int 10, Wis 10, Cha 1
Base Atk +3; CMB +4; CMD 14 (can’t be tripped)
Feats Improved Initiative, Skill Focus (Perception), Skill Focus (Stealth)
Skills Climb +10, Perception +8, Stealth +16; Racial Modifiers +4 Stealth
A slithering tracker can engulf a paralyzed foe up to one size larger than itself as a standard action. It cannot make a slam attack during a round in which it engulfs. The slithering tracker merely has to move into a space occupied by a paralyzed creature, completely covering it.
A slithering tracker drains the body fluids from an engulfed opponent. Each 5 minutes an opponent is engulfed, it takes 1 point of Constitution damage. Because it takes a long time to completely drain a foe, a slithering tracker generally only uses this ability against a paralyzed, stunned, held, or sleeping opponent.
A slithering tracker is hard to identify, even under ideal conditions, and it takes a DC 15 Perception check to notice one. Creatures who fail to notice a slithering tracker and walk into it are automatically hit with a slam attack and subjected to the creature’s paralysis attack.
Environment any underground
The slithering tracker is an amorphous and transparent creature that inhabits dark underground areas of the world. Unlike other oozes, the slithering tracker does not feed on organic matter. It survives by devouring living creatures.
A typical slithering tracker is 3 feet long and has a thickness of about 6 inches. It can grow to a length of about 8 feet.
A slithering tracker prefers to attack helpless or immobile opponents. Once it paralyzes an opponent, the slithering tracker flows over it and drains its body fluids. The tracker, now sated, slithers off to digest its meal. All that’s left of the opponent is a dry and rotted husk.
Slithering Tracker from the Tome of Horrors Complete, Copyright 2011, Necromancer Games, Inc., published and distributed by Frog God Games; Author Scott Greene, based on original material by Gary Gygax.