Apparently paths are the easiest way to make a spiral. But I'm using a spiral for a particle curve guide and Path doesn't work with Curve Guide. So I'm just wondering if it's possible to turn the curve from Path to like the thing that the Bezier is like?
Under Edit Mode in the Tools tab of the Tool Shelf there is a button labeled Set Spline Type to switch between several curve types like Poly, Bezier or NURBS.
Under 2.8+ this can be set from the 3D View header menu > Curve > Set Spline Type.
Spline type is stored as a per-curve spline property. A spline is any connected sequence of vertex in Edit Mode within a single curve object, that means each different spline within a curve can have its own independent type.