BOZ said:
actually, i copied "opportunity attacks" from the gelatinous cube entry.
Ahh, WOTC, kings of consistency.
Here's an attempt at rewriting the Stampede ability to address some of the issues.
Stampede (Ex): If 20 or more nic’Epona gather together in tight ranks, they can move as one creature, much like a swarm. A stampede fills a 60-foot space, and this space increases by 20 feet for every 10 additional nic’Epona over the minimum 20.
Movement while stampeding is similar to aerial movement. Treat the nic’Epona stampede as having a maneuverability class of average. Thus, the stampede must maintain a forward movement of half speed, or break up into individual nic’Eponas at the end of its turn. It can make a maximum turn of 90 degrees, and can use 5 ft. of its movement to turn 45 degrees. The stamped cannot move backwards.
The herd must be at least 150 feet away from their nearest target to build up enough speed to form a proper stampede. The stampede can move through any area containing a creature of Large size or smaller. Opponents can make opportunity attacks against individual nic’Epona within the stampede, but if they do so they are not entitled to a saving throw. All targets in the area suffer 10d6 points of bludgeoning damage for every 20 nic’Epona present in the stampede (Reflex save DC 17 for half). The save DC is Strength-based.
Stampeding nic’Epona are immune to fear (magical or otherwise).