Monster Stat #9:  Yig
  (from Adventurers #86)

frequency             very rare
# appearing           1-3
climate/terrain       anywhere near illithids
movement              12"
armor class           3
HD                    12
thac0                 9
# of attacks          3
damage/attack         5-16/5-16/Special
special attacks       brainsuck
special defenses      see below
magic resistance      90%
intelligence          Semi-
alignment             Lawful Evil
size                  L (8')

  Yigs are weird reptillian monsters bred by the illithids,
who use them for labor and musclepower.  A yig has a tall,
broad body, covered with glistening green scales.  Its
eyes are large, round, and multi-faceted, but stranger yet
is its mouth, which consists of a cluster of foot-long pink
tentacles.  Though the thing can strike with its powerful
arms, it will always prefer to use its tentacles to suck
the brain from a foe.  If this attack is successful, the
unfortunate victim is stunned, unable to move, think, or
act; at this point, brain-eating commences.  The numerous
tentacles will quickly burrow into through the skull of
the victim, who will lose 4 points of intelligence per
round, permanently; when this stat drops below zero, the
victim is dead.  Note that even healing magic cannot bring
back a brain lost in this gruesome manner.
  Besides its high magic resistance, yigs are totally
immune to all mental attacks, including psionics.  They
are essentially illithid soldiers in the arena that the
illithids don't deal with:  heavy-duty physical combat.
Obviously, the yigs are highly feared by all intelligent
denizens of the Underdark, especially drow.