A Ultralocrian
A · B♭ · C · D♭ · E♭ · F · G♭
The seventh mode of harmonic minor, A Ultralocrian is a Super Locrian scale with the seventh flattened twice, so it spells out a diminished seventh chord over an altered root. It's about as tense as a scale gets, used over altered dominants resolving into minor keys. Deep jazz territory.
Left-handed