The reality TV star's beau was wielding a bloody axe as part of his costume for the American Psycho themed party at 1Oak Nightclub at the Mirage Hotel in Sin City on Saturday night.
Posing for pictures by himself Scott showed off his costume which, with suspenders, dark sunglasses and vintage walkman headphones paid homage perfectly to the sadistic character of Patrick Bateman who was played by Christian Bale in the 2000 film.
New reports have recently surfaced suggesting he is back to his wild ways, partying and boozing while Kourtney looks after his children.
RadarOnline.com even reported that the 29-year-old was spotted snuggling up to a "hot blonde" in Connecticut during a night at the Vista Lounge in Mohegan Sun Casino just a couple of weeks ago.
The Daily's Flash claimed that on the same night Disick acted "incredibly mean" to his waitress and "ripped the bottle" out of her hands before "dumping drinks" on her.
Scott is however still hoping to make an honest woman of Kourtney and was spotted shopping for an engagement ring in Fort Lauderdale, Florida on October 18.
"Scott was most definitely shopping for engagement rings," an onlooker exclusively told RadarOnline.com.
"Scott and his friend looked at a whole selection of amazing rings, all diamond, all different cuts, sizes, settings - he certainly is taking his time and wants to make the right purchase."