Depending on what preceeds it, that could also be another "Dan" chord if it followed a Bma7 chord, a la "Peg". From Bottom to top:
B A# D# F#
Bb Ab Db Gb (enharmonic)
A G# C# E
G# F# B E
In this context, it's just a fancy "fusion" IV-I6 progression ( "I6" in the figured bass sense of the term), in which case I'd have to agree with HOT TAMOLEY that the mystery chord in question would function as a first inversion Gb (F#) chord with a ninth.
I used to play in a fusion band led by a great guitar player who wrote all the tunes, and he always notated our "mystery chord" as a min7#5 - in our case, Bbmin7#5 - because where he studied harminy, he was instructed to always put altered color tones on top. I tried the argument that what was on top was really the root, but it only annoyed him, so I just learned to translate. I'm tempted to think that
JIZZ' chord fits this mold because of the Bb Phrygian reference, which is really just another way of thinking of the same note set as Gb Ma.
(look out for Pacman, he HATES IT when I say stuff like that!

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