Earthquake Stomp

(Secrets of Xen'drik, page 134, DnD 3.5)

[General]

Your thunderous steps allow you to knock smaller enemies off their feet.

Prerequisite

STR 25, size Large or larger

Benefit

As a standard action, you can stomp the ground so furiously that nearby creatures fall prone. All creatures within 10 feet of you whose size category is at least two smaller than yours can be affected. For example a Large creature can affect Small or smaller creatures, a Huge creature can affect Medium or smaller creatures, and so on. Treat this as a trip attack against all affected creatures, except that you need not make a touch attack (and so do not provoke attacks of opportunity), and enemies not knocked prone cannot attempt to trip you in return.