Pirahna Bats
Created by David Dougher

FREQUENCY: Very Rare
NO. APPEARING: 10-300
ARMOR CLASS: 5
MOVE: 48”
HIT DICE: 1 hit point plus special
(see below)
% IN LAIR: 100%
TREASURE TYPE: Nil
NO. OF ATTACKS: 1
DAMAGE/ATTACK: 1
SPECIAL ATTACKS: See below
SPECIAL DEFENSES: None
MAGIC RESISTANCE: Standard
INTELLIGENCE: Animal
ALIGNMENT: Neutral
SIZE: S (6” long)
PSIONIC ABILITY: Nil
    Attack/Defense Modes: Nil

Pirahna bats have an appearance
much like that of normal bats in most
aspects, but possess relatively large, distended jaws filled with razor-sharp teeth.
They are found in swarms of various
sizes inside caves and caverns or in other large enclosed areas such as a chamber in a castle or dungeon. They will be
sleeping 30% of the time when encountered, but there is only a 10% chance that
a sleeping swarm will not be awakened
by the presence of other beings or the
noise the intruders create. Their movement, like that of normal bats, is guided
by a sonar-like sense which enables
them to fly and attack with accuracy
even in total darkness.

Pirahna bats’ most distinctive characteristic is their ability to increase their
strength when attacking in a swarm. Although each individual bat has only one
hit point and thus (if attacking as an individual) only attacks as a monster of one
hit die, a swarm will attack with an effective hit-dice number equal to the number 
of bats in the swarm divided by four
(round down). For instance, a swarm of
25 bats attacking all at once will score a
successful hit as if the swarm were a
monster of 6 hit dice. In no case will more
than 30 bats attack as a swarm against a
single target at one time, and only one
swarm can attack a single target at one
time.

When a swarm scores a successful hit,
it is assumed that only one-fourth of the
bats participating in the attack will actually hit the target (the other three-fourths
serving to confuse the opponent). Thus,
a swarm will always score a number of
points of damage equal to the effective
hit-dice number it used to determine
whether or not a bit was made; a swarm
of 25 bats, if it hits, will do 6 points of
damage, and a swarm of 30 (the maximum possible in one attack) will do 7
points of damage if the attack succeeds.
Whenever combat or other circumstances reduce the number of Jive pirahna
bats to less than 10 (the minimum which
may be initially encountered), the remaining animals will attack as individuals with one hit die each. 

The “combining” ability does not apply on defense; an opponent who scores
a hit,will kill a number of bats equal to the
number of points of damage in that attack. Bats which survive an opponent’s
attack may not attack again themselves
until the second round following the first
attack, because the bats will take one
round to turn and dive on the target
again. Surviving bats from two or more
swarms may combine into one larger
swarm for subsequent attacks, as long
as the maximum of 30 bats per attacking
swarm is not exceeded. The number of
bats which form into one swarm at any
given time can be determined randomly
or at the discretion of the DM. 

Although pirahna bats generally possess standard magic resistance, they are
especially susceptible to Sleep and Slow
spells. Sleep will affect twice the usual
number of victims, and Slow will affect a 
number of bats equal to the level of the
caster multiplied by two, with those affected by the spell dropping to armor
class 10 for the duration.

Pirahna bats do not like the effects of a
Continual light spell or any spell which
creates flame, and when confronted with
such magic will usually flee. However,
Light spells or the flame from a normal
torch will usually only infuriate them and
cause them to attack at once.

As the “pirahna” part of their name
indicates, these creatures are particularly vicious and they become frenzied after
blood is drawn. There is a 50% chance
that all surviving bats in a swarm will
converge on a target which has been
rendered dead or immobile, forsaking ail
other possible opponents and proceeding to strip all the flesh from a “sitting
duck” unless the swarm is opposed in
this attempt. This 50% chance should be
rolled for once every other round until
the bats do converge on the stationary
target or until the issue is resolved in
some other fashion. 

For every 30 bats encountered, there is
a 5% chance that one of them will be
vampiric and (as per the procedure outlined above) a 25% chance that one of
the bats which actually bites an opponent will be the vampiric one. 


Dragon - Monster Manual III - Dragon 51

 
 
Dragon - Monster Manual III - Dragon 51