Alcubierre's mist cloud around an UFO, seems to be the a sign of the oscillating vacuum propulsion system.

In Quantum FFF Theory, it is known that the vacuum is full of oscillating Axion particles forming the Dark Energy of the vacuum, as one of the vector particles together with the gravitons to originate quantum gravity.
Around Black Holes we assume that no gravitons come out of the black holes, so ONLY the vacuum is responsible for gravity around the black hole. Even around micro black holes like Ball Lightning , Comets and Sprites.

see also the origin of inertia . 

Even micro Black Holes (ball lightning) are assumed to be NON Inertial. and related to some UFOs? 

Even Magnetic UFOs seem possible: see

"Different Levitation Systems Observed in Big Basin UFOs, EMEC and Anti Maxwell Effect and Free Energy.

see: https://vixra.org/pdf/2006.0130v2.pdf

and see: https://bigbang-entanglement.blogspot.com/

Secondly:

all Black Holes are massless! see "the Hand of God" in space with a ring of former starspot black holes and one neutron star below.