Strange 'Jimmy Cagney' style dressed men who act in the classic psychic vampire manner. They primarily 'attack' those who seriously investigate UFO phenomenon. They harass and annoy, bullying themselves into your house, question you on what you know and then make veiled threats causing terror and then leave. Not vampiric you say? Vampires will harass and annoy you to be let in to your house because classic vampire law says that you have to invite them in over the door step. Psychic vampires feed on fear, and so they induce fear. Men In Black will become disorientated if you call their bluff or laugh at them. This is how you defuse a psychic vampire (or a bogart incidentally).
They also mention the Illinois Enema Bandit (sorry, Frank Zappa reference there...)
so MIB vampires?
'...The vampires of folklore - undead, imbecilic parasites sharing little in common with the cliched gothic creations of Anne Rice et al - were as likely to be satisfied by animal blood as by human (I"m a vegetarian vampire Bella.' yeah right!). Cattle and horses were particularly liable to be attacked (indeed, the wasting diseases suffered by farm animals were often blamed on the activities of vampires). In modern times, animal mutilations are frequently associated with night-time UfO activity...
One such incident occured in December 1968, when Idaho farmer Lonnie Duggan heard a commotion in his barn and discovered "a strange looking little man covered with fur" drawing blood from a horse with a huge syringe. The little man explained that he was from Tau Ceti and that his people had been visiting the Earth for the last 100 years. Then he warned Duggan to return to the farmhouse and stay there for half an hour. Shortly afterwards, a huge glowing object rose up from behind the barn and shot away "like lightning".
Of course, not all vampires hunger for blood. In New Age and occult circles there is a widespread belief in 'energy vampires', which feed off their victim's lifeforce. Although the term generally refers to fellow humans who have mastered the art of sapping others' psychic energy, it may also be used of non-corporeal beings. Many Ufo and entity witnesses have reported feeling utterly drained of energy in the aftermath of their encounters, often requiring weeks to fully recover. This is generally dismissed as a mere side-effect of their experience, but one might equally speculate that the draining of energy was actually the whole purpose of the encounter.
Of all the bizarre entities terrorising our demon-haunted world, the Men in Black perhaps come closest to resembling the Western theatrical concept of the vampire. Dr Herbert Hopkins, for instance, described the MIB who visited his home as having a "dead white" coloured face and "vivid red" lips. The lip colour was due to make-up rather than recent blood-feeding, but nevertheless the implications of the image are striking. The MIB seemed able to exert a kind of hypnotic spell over Hopkins, and performed a peculiar kind of parlour trick in which he made a coin apparently dematerialise. It may be significant that the strange visitor left complaining that his energy was "running low". Perhaps he had found himself somehow unable to feed off Dr Hopkins' lifeforce.
... UfO mythology has been dominated by the fragile yet demonic figures of the greys. Like the vampires of melodrama, the greys fly into our bedrooms at night and mesmerise us with their shining, compelling eyes. And like the more authentic vampires of folklore, the greys act in a highly repetitive, almost instinctual manner - descending in swarms to steal our vital fluids before returning home to their otherworldly roosts. Unlike the campy vampires of stage and screen, the greys utterly lack personal charisma and make no attempt to seduce us or to win us over to their side. They simply take what they need and move on. Such, alas, is the unglamorous, pragmatic way of all true parasites...'
from the UK site Cabinet of Wonders
Mind monster? I'd say so. Great fancy dress costume :) But an aspect I hadn't encountered before. And then, MIB appear to those that dabble in Ouija and many report suffering from aggressive poltergeist activity. I would say, that people who 'dabble' in supposed paranormal channeling activities such as tarot, ouija, spirit contact, in fact religious activity of any sort, has a mind that is more 'open' to interference from 'the other realm', and are therefore more likely to encounter visits. Psychologically, we seek spirituality like we seek love, and like love, sometimes spirituality blurs the boundary between reality and lucid dreaming. Like love, sometimes it can grow out of control, in good ways
or bad. The world is not multi-dimentional, but our minds are. So are MIB vampires? Why not?