Author's Note: There's good reason for this Mature rating, people. While it's not all that explicit, it shows just why the last living male of the Black wizarding family is truly deserving of the description of 'horndog' at any time, any place, any universe, even an AU like the following.
Wham!
Sirius Black landed flat on his back on the ground, with that man's breath being promptly smashed out of him, so that for the next few moments, as he struggled for air, that gasping wizard just didn't have the time to consider his unlikely survival after losing his recent magical duel with his insane cousin Bellatrix that had sent him falling through the Veil deep in the basements of the Department of Mysteries, just a second ago.
Er. About the last, wasn't that supposed to be absolutely fatal? Yet here he was, right this minute lying on soft earth, smelling the crushed grass under his suit outfit, looking up at the night sky, and hearing loud, frightened screams coming from his left-
Hastily rolling over onto that side of his body, Sirius stared in total bewilderment at the darkened Muggle house beyond the lawn he was occupying. In the next second, the screams came again that clearly expressed their senders' abject terror. The only situation that could produce exact noises like that, in Sirius' unfortunately extensive experiences as a member of the Order of the Phoenix, was that the screamers were at present in the process of being horribly murdered.
Without even thinking about it, Sirius scrambled to his feet and ran directly towards the unlit house, his wand that he'd never lost his grip on despite everything held out before himself. As he got within a few yards of the front door of the house where the screaming was still continuing inside, Sirius pointed his wand at that panel, hastily muttering the proper spell to open the door he was rapidly rushing towards.
"Alohomora!"
A tremendous inward throb shuddered throughout the wizard's entire magical core, and the front door completely vanished into thin air. Still running at his full speed regardless of currently being in sheer shock at what had just happened, not simply of what he'd just experienced, but also due to the fact that his low-power spell definitely shouldn't have done that, Sirius burst through the now-open house doorway and into the darkened building.
Skidding to a stop in the front hallway lest he collide with or trip over some piece of Muggle furniture, Sirius bellowed "Lumos!", with the wizard expecting the appearance at the tip of his wand the normal small ball of glowing light that'd help him see what was happening inside the house.
In unison with another immense shudder of his magical core, a yard-wide white globe blazing in its brightness at eyeball-searing levels then burst into existence just beyond Sirius, floating in mid-air at his chest level, until a dumbfounded man made the proper quick flick of his wrist that'd tone down his overpowered spell. The painful light immediately dimmed to its usual level of illumination, revealing a startling scene in the front room of the house.
In the furthest corner of that space, three young women were huddled together on the floor there, arms wrapped around each other and uselessly pressing themselves further back against the walls, their mouths still agape to deliver the constant screams they'd been uttering the last few seconds, but now simply hanging open as these females' tear-streaked faces stared in stupefaction at their unexpected visitor standing in the hallway and holding some kind of stick that had a ball of light floating in front of this, that a moment ago had been brighter than the sun.
The final member of the current inhabitants of the house was the only one not wholly taken aback at this moment. Instead, Michael Myers smoothly spun around and then he implacably strode towards the interrupter of that escaped lunatic's murder spree of tonight's prey and her friends on this Halloween holiday. That monster's right hand lifted high his deadly, razor-sharp knife in preparation for butchering his latest victim.
Blankly regarding through the slits of his white mask the man that was pointing a little stick at him, Michael didn't bother thinking about how strange this was, only that he'd soon take care of a minor problem and then get back to slaughtering the three women, who were themselves all watching with terrified dismay their potential savior standing there and about to be killed.