Eldritch Serpent (3.5e Invocation)

When you use this blast shape, your eldritch blast takes the form of a serpent which coils around you. While active, you cannot use your eldritch blast, though you can dismiss it as a swift action. The snake can attack on your turn once per round as a free action, making an eldritch blast attempt out to a range of 15 ft and threatening out to a range of 5 ft (or your normal threat range for a creature of your size, whichever is larger). It can make an eldritch blast as an attack of opportunity.