Needs review
Source: Draconomicon

Description: You can strike the ground with your tail so hard it knocks other creatures down.

Prerequisites: STR 13, Power Attack, Size Large or Larger, Dragon

You may, as a full-round action, strike a solid surface with your tail and create a shock wave that radiates out from your space and continues for a number of feet equal to 5 × your racial Hit Dice. Make a bull rush attack by rolling once regardless of how many creatures are in the radius. Every creature in the radius makes a Strength check and compares it to your roll. Those who fail their opposed checks are knocked down.

Special: Structures and unattended objects at least partially within the shock wave take damage equal to 1d6 + your Strength bonus.