Seasons Greetings
(2015)

This is a Christmas horror anthology comprised of 4 short tales:

Oh Christmas Tree!
Ava (Brittany Blanton) and her boyfriend Phillip (Mike Reeves) walk into the woods to get a Christmas tree. As Ava prattles on about decorations, Phillip is quiet, giving short responses. Finally, Phillip takes the ax he obstinately was going to use to cut down a tree and instead uses it on Ava, killing her and wishing her "happy holidays." 

Elfis 2
An elf decoration turns out to be alive and murders a woman and her boyfriend with a butter knife. The woman's teenage son, who did not hear the murders due to listening to music, discovers the bodies and runs out the house in terror.

Ladies Night Before Christmas
While Elaine is on vacation in Palm Springs, serial killer buddies Frankie (Amanda Collins) and Camille (Kayla McDonald) return to a old hunting ground. Passing by a new trio of men, they proceed to get invited in for drinks. They then proceed to murder the three men and then drive off, getting away with murder once more.

Unholy Night
In a sequel short to Summon, it is revealed that Phillip is the boyfriend of Analise (Ayse Howard), and thus had been cheating on her with Ava. Phillip finds a book outside their apartment and shows it to Analise who promptly freaks out. It is the spell book she and Kimber had used to summon a demon. When Analise returns to talk to Phillip, she finds him on the ground writhing in agony, with a loud ringing in his ears. The demon Niree (Erin R. Ryan) is standing over him. Analise collapses to the ground in disbelief as Niree explains she has come for her. Phillip meanwhile is being tormented by the ghost of Ava (brought upon by Niree), who scolds him for killing her and their child and breaks his neck. Niree tells Analise that she is punishing her "for cutting corners" and summoning her in the first place. Analise screams as loud ringing begins in her ears and it is implied Niree kills her too.

The film ends with Niree walking down the deserted street at night.  

Thanks Tim (Spectre)!