piano scale
E♭ Phrygian
E♭1F♭♭2G♭♭3A♭4B♭5C♭♭6D♭♭7
Minor with a flattened second — the half step right above the tonic is the whole character.
The same sounds spelled from the other side are D♯ Phrygian.
Written out
Every accidental is written in, rather than left to a key signature, so the letters can be read one at a time.
The step pattern
E♭HF♭WG♭WA♭WB♭HC♭WD♭WE♭
What is true of it
E♭ Phrygian is E♭, F♭, G♭, A♭, B♭, C♭ and D♭, and back to E♭.
Its steps are H – W – W – W – H – W – W, where W is a whole step and H a half.
It costs 7 alterations to write — near the limit of what a key signature can carry.
On the same tonic, E♭ natural minor differs from it by exactly one note.
Chords made only of these notes
D♭mminorD♭m7minor seventhE♭mminorE♭m7minor seventhG♭majorG♭7dominant seventhA♭mminorA♭m7minor seventh
Found by testing every chord in the catalogue against these 7 sounds, not chosen.