Universal Monster Rule

If a creature with this special attack begins its turn with an opponent grappled in its mouth (see Grab), it can attempt a new combat maneuver check (as though attempting to pin...

The creature can mentally communicate with any other creature within a certain range (usually 100 feet) that has a language.

As a full-round action, a creature with the trample ability can attempt to overrun any creature that is at least one size category smaller than itself.

The save DC against a creature's trample attack is 10 + 1/2 the creature's HD + the creature's Strength modifier.

Sensitive to ground vibrations; automatically pinpoints the location of anything in contact with the ground within the specified range.

A creature with the trip special attack can attempt to trip its opponent as a free action without provoking an attack of opportunity if it hits with the specified attack.

Undead are immune to death effects, disease, mind-affecting effects, paralysis, poison, sleep, stun, ability drain, energy drain, nonlethal damage, physical ability score damage/penalties, fatigue, and exhaustion.

The creature uses manufactured weapons as if it were one size category smaller than the creature's actual size.

Animals do not willingly approach the creature unless the animal's master makes a DC 25 Handle Animal, Ride, or wild empathy check.

A creature with vulnerabilities takes half again as much damage (+50%) from a specific energy type, regardless of whether a saving throw is allowed or whether the save is a...

A creature with this special ability can breathe underwater indefinitely.

A creature with this special ability can survive out of water for 1 minute per point of Constitution.

Creatures with the web ability can use webs to support themselves and up to one additional creature of the same size.

Some creatures can transform themselves into whirlwinds and remain in that form for up to 1 round for every 2 HD they have.