Sickening Blast

Warlock Invocation
Level: Least, 2nd lv.
Components: V, S
Casting Time: 1 standard action
Range: 60 feet
Duration: 1min
Saving Throw: Fort
Spell Resistance: No

This eldritch essence invocation allows you to change your eldritch blast into a sickening blast. Any living creature struck by a sickening blast must make a Fortitude save or become sickened for 1 minute. A sickened creature struck by a second sickening blast is not affected by the sickening aspect of the blast but still takes damage normally.

(Complete Arcane, Page 135)