[Many of you may recognize the inspiration for this monster, the Clark
Ashton Smith story 'The Monster of the Prophecy'].

The Worm of 1000 Cuts is an insidiously evil product of dark sorcery,
a 10-foot worm-like creature with small, shiny black scales covering
its entire length. Each articulating scale is covered with dozens of
tiny, razor-sharp tentacles that move and squirm independently. The
Worm will be found alone, typically lining damp, earthen pits where it
can latch onto unfortunate falling victims, literally cutting them to
death a little at a time. The Worm is also a favored method of
torture, used by evil High Priests of Tzortha, who lower bound victims
repeatedly into Worm-lined pits and pull them back before death can
free them.

A successful roll to-hit against a victim means they have latched on
that round, doing 1d6+2 damage and doing an automatic 1d6+2 damage in
subsequent rounds, until they are forcibly removed or the victim is
dead. PCs can remove an attached worm, with a successful roll to-hit
the creature is flung away, but takes no damage that round. Those
wearing metal armor always take half damage from Worms of 1000 Cuts.

Worm of 1000 Cuts*

+------------+---------------+
|AC          |5 [14]         |
+------------+---------------+
|HD          |4              |
+------------+---------------+
|ATK         |1d6+2 razor    |
|            |tentacles      |
+------------+---------------+
|SP          |Latch on       |
+------------+---------------+
|MV          |6              |
+------------+---------------+
|HDE/XP      |5/240          |
+------------+---------------+
|SAV         |15             |
+------------+---------------+
|BHB         |+4             |
+------------+---------------+
|AL          |Chaotic        |
+------------+---------------+

* Stat block above is for Swords & Wizardry Whitebox (or OD&D, Delving
  Deeper, etc.), where HD are d6-based. For other S&W editions, or for
  Labyrinth Lord, use 1d8 as a base for both HD and damage.