Draconic Presence( Races of the Dragon, p. 104)
When you use your magic, your mere presence can terrify those around you.
Draconic Heritage (RDr) , sorcerer level 1st,
Whenever you cast an arcane spell, opponents within 10 feet of and with fewer Hit Dice than you become shaken for a number of rounds equal to the level of the spell you cast. A Will save (DC 10 + level of the spell cast + your Cha modifi er) negates the effect. A successful save indicates that the opponent is immune to your draconic presence for 24 hours. This ability does not affect creatures with an Intelligence of 3 or lower or creatures that are already shaken, nor does it have any effect on dragons.