Weapons Description

Lasso

A lasso is little more than a thin rope knotted with a slipknot that creates a large loop. The loop is thrown at a target and the other end is pulled when the loop strikes, causing it to tighten around the target. You can throw the lasso at a Medium-size or smaller target, which requires a ranged touch attack. If the touch attack succeeds, you immediately start a grapple against the target with a -4 penalty on your roll (all normal grapple modifiers apply). If the opponent is grappled by the lasso, you may use an attack to attempt to trip the target. If you are tripped during your own trip attempt, you can drop the lasso to avoid being tripped. You cannot damage or pin the opponent with the lasso, and you are not considered to be grappling when using the lasso to grapple. If you drop the lasso, the grappled creature only needs to succeed at a DC 10 grapple or Escape Artist check to get out of the lasso.
If you secure one end of the lasso to the saddle of your mount, you can use the mount's size and strength modifiers for your grapple checks.
The maximum range for a lasso cannot exceed the length of the rope, minus 5 feet.

From Book of Exalted Deeds: A lasso is an entangling weapon that deals no damageH but it entangles only parts of an opponent's body. When you use a lasso to entangle your opponent's arms, you make a ranged touch attack against your target. A lasso's maximum range is 4 feet. If you hit, the target is partially entangled, taking a -2 or] attack rolls and a -4 penalty on effective Dexterity. The creature's speed is not reduced, and it can still charge or run, but you control the trailing rope by succeeding at an opposed Strength check while holding it, the lassoed creature can only move within the limits that the rope allows. If the lassoed creature attempts to cast a spell, it must succeed on a DC 15 Concentration check or be unable to cast the spell.

The lassoed creature can escape with a DC 20 Escape Artist check as a full-round action. The lasso has 2 hp and can broken with a DC 23 Strength check—also a full-round action. Alternatively, you can use a lasso to make trip attacks. If you are tripped during your own trip attempt, you can drop the lasso to avoid being tripped.

Preferred weapon of: No known deity.