FREQUENCY: Very rare ([Tropical Wilderness Mountains], [Tropical Wilderness Hills])])
FREQUENCY: Very rare ([Dungeon Level III])
NO. APPEARING: 1-2
ARMOR CLASS: 2
MOVE: 12" (3")
HIT DICE: 3
% IN LAIR: 80%
TREASURE TYPE: 10-60 gems (base 10 g.p.)
NO. OF ATTACKS: 1 and 1
DAMAGE/ATTACK: 4-32/2-12
SPECIAL ATTACKS: Heat
SPECIAL DEFENSES: Fire attacks heal
MAGIC RESISTANCE: Standard
INTELLIGENCE: Low
ALIGNMENT: Neutral
SIZE: S
LEVEL/X.P. VALUE: III | 65 + 3

It is suspected that this beast is a larval form of Some creature of the
Elemental Plane of Earth or the Elemental Plane of Fire, though some
postulate that its origin is an Elemental Plane so far undefined. It is
shaped like a small purple worm 2' in diameter and 4-5' long. In
colour it is a reddish-silver.

The creature lives on the PMP in rock through which it can burrow at the rate of 30' per turn,
creating a red-hot tunnel about 3' in diameter. The tunnel remains hot
for two turns after construction; in the first turn the rock is a red
colour and inflicts 4-14 hit points of damage on anyone touching it
with bare skin, but in the second turn the rock returns to normal
colour and a touch inflicts 2-7 HP of damage. No saving throw
is permitted in either case, though particularly in the first turn discemable
heat will be radiated from the rock.

In melee the creature will initially charge at an opponent, being able
to move at 48" rate for this short burst over a distance no greater
than 30'. If the charge hits a victim, he will suffer 4-32 hit points of
damage from the heat and the momentum of the charge. Thereafter
its mode of attack is simply to touch a victim for 2-12 hit points of
heat damage, reverting to normal speed after the intial charge.

When a victim is struck by an attack by a thoqqua, whether as a result
of a charge or normal attack, the prominent items he is wearing or
carrying on the side of his body at which the attack is directed must
save against normal fire or be rendered useless. If the attack is a
charging attack, these saving throws are made at -4.

Fire attacks heal: If a thoqqua is struck by a fire attack it temporarily (1-4 turns) adds the damage to its hit points.

However cold attacks inflict double damage on the creature.
 

by Nicholas Riggs