Scorpio is first shown in Photo-Lettering’s Psychedelitypes (1968) as Psychedelitype 5882. No lowercase. Their Ballard is the same design with the bottom rounds cut off.
Hoopla is a very similar design, but with rounder bottom (see esp. ‘C’ or ‘S’) and a (non-descending) lowercase. Shown in a Lettergraphics catalog from 1976 (but not in one from 1969).
Various digital interpretations including “BellBottom (Fantazia, many anon), BellBottom.Laser (Lorvad), Groovy (A&L), Balloon (Brendel). Shown in Solo Art Deco Alphabet book as Colonel Hoople.” [Solopedia] Doobie is a commercial digitization and used for this sample.