Heighten Breath
(Draconomicon, page 70, DnD 3.5)
[Metabreath]
Your breath weapon is even more deadly than normal.
Prerequisite
CON 13, breath weapon
Benefit
You can increase the save DC of your breath weapon by any number up to a maximum equal to your Constitution bonus. For each point by which you increase the save DC, add +1 to the number of rounds you must wait before using your breath weapon again.