Flank Attack

Flank attack is a druid skill that requires the druid to be in dire wolf
form.  In the heat of a fight, you can try to flank your enemy's defenses 
and bite his neck.  Flank attack can only be used on an enemy which is
currently fighting. For mobs, there is a delay of 1 round after using 
flank attack.  When using it against players, there is a delay of 2 
rounds.

> flank attack

The classes that get the skill flank attack are:

druid      : Level  90 (excellent)

See:
Dire Wolf Form