There is a good set of rules in Letters of the damned 6
Chained Attack Squig
10 Gold Crown, Availability: Common (Orcs Only)
Small, vicious attack squigs are often herded towards the
enemy by orcs and goblins in battle. Orcs of status may
find the time and patience to train an attack squig as a
pet and guard animal. An orc will normally keep his
attack squig chained to his arm, and will merrily throw
or swing his squig into combat when engaging the
Range: Close Combat
Strength: 3 (cannot be modified)
Cannot be Parried: A squig’s master will often use his
pet’s chain to swing the beast onto his opponents. Such
attacks frequently result in the squig’s chain wrapping
about, delivering the creature to the victim’s rear.
Attempts to parry such an attack are futile. A model
attacked by an attack squig may not make parries with
swords or bucklers.
Strike First: A squig's chain is long, and the voracious
critter literally leaps at the prospect of a meal. If charged,
an orc’s attack with a chained attack squig will ‘strike
first’, using an Initiative of 3.
Gnawing bite: An attack squig may only be used to
make one attack per round. All other attacks must come
from another weapon. However, should an attack from a
squig make a successful hit, the little monster will remain
attached to its victim until dislodged. When the squig
hits, it attempts to wound with a strength of 3.
Furthermore, in every additional round of combat
between the orc and the squig’s victim, the squig makes
an automatic strength 3 hit. The squig is pulled off if 1)
its master is knocked down, stunned, or taken out of
action, 2) either combatant flees or otherwise leaves
combat, 3) the victim is taken out of action, or 4) the
victim is knocked down or stunned, and the orc is facing
additional, standing opponents.
Doesn’t Mind Well: Although an attack squig is
normally chained to an orc’s wrist, it lunges and pulls at
its chain. Managing the little hellion requires the full use
of the orc’s arm. No other weapon, shield, or item may
be used in one of the orc’s hands during the battle. Note
that the orc may use missile weapons with no penalty
(provided his other arm is intact!).