This creature appears to be a large snake formed of earth and sand. A slit seems to function as the creature’s mouth.
Sandling CR 2
Speed 30 ft., burrow 20 ft.
Melee bite +6 (1d8+4)
Space 10 ft.; Reach 5 ft
For every 2 gallons of water that hit a sandling, it is slowed (as the slow spell) for 1 round (no save).
Environment Elemental Planes of Earth
Sandlings are creatures from the Elemental Planes of Earth. A sandling in its natural form resembles a mound of sand that covers a 10-foot area. They are most often summoned to the Material Plane by clerics and wizards, though on occasion a sandling slips through a vortex connecting the Elemental Planes of Earth to the Material Plane. Sandlings live on a diet of minerals only and cannot digest plants, herbs, meat, or other substances. Opponents killed by a sandling are left for scavengers.
Sandlings have no real society and are highly solitary in nature. Though they harbor no ill-will towards others of their kind, it is very rare to find more than one sandling operating near another. Reproduction methods among sandlings is unknown to sages but it is believed they create others of their kind by division (that is, an adult sandling splits into two or more smaller creatures).
A sandling lies in wait in its natural form until it detects an interloper in its territory. It then assumes its serpentine form and attacks with an abrasive bite.
A typical sandling is 10 feet long but can grow to a length of 20 to 25 feet.
Sandling 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 Lawrence Schick.