The creature can grab opponents much smaller than itself and hold them in its mouth or claw.
Prerequisite: Size Huge or larger.
Benefits: The creature can choose to start a grapple when it hits with a claw or bite attack, as though it had the improved grab special attack. If the creature gets a hold on a creature three or more sizes smaller, it squeezes each round for automatic bite or claw damage. A snatched opponent held in the creature’s mouth is not allowed a Reflex save against the creature’s breath weapon, if it has one.
The creature can drop a creature it has snatched as a free action or use a standard action to fling it aside. A flung creature travels 1d6×10 feet, and takes 1d6 points of damage per 10 feet traveled. If the creature flings a snatched opponent while flying, the opponent takes this amount or falling damage, whichever is greater.
Source: Monster Manual