Bb Minor 9b5, 3rd inversion (G# in the bass)
Also written as Bbm9b5/G#.
Notes, from the bass up
G# (bass)B#A#C#E
The same notes as Bb Minor 9b5 (G#, B#, A#, C# and E), rearranged so G# is the lowest note. Use it to move between chords with smaller jumps across the keyboard.