It is Tales from the Darkside: The Movie
...Along the way, Preston stops to relieve himself in the back alley.
While there, his friend sees and then shoots at the gargoyle monster,
but it brutally severs his hand and decapitates him. Preston witnesses
the horrific scene. Terrified, he tries running away, but the creature
corners him. It spares Preston's life when he swears never to reveal
what he saw or describe its appearance to anyone. The monster then
scratches Preston's chest saying, "Cross Your Heart," then vanishes.
Preston is traumatized and confused, but bound by his oath, can say
nothing about what happened.
The horrified Preston runs into another alley where he sees a
beautiful woman (Rae Dawn Chong) passing by. After grabbing her, he
assures the woman she will not be harmed. The woman, Carola, claimed
she became lost while going to meet friends and was searching for a
taxi. Preston convinces her to call a taxi from his apartment. While
there, Carola cleans the gargoyle-inflicted wound on Preston's chest,
then they make love.
Preston's life soon improves and his struggling art career becomes
wildly successful, mostly thanks to Carola's connections. They
eventually marry and have two children. However, Preston is tormented
by memories of the gargoyle, and his vow of silence weighs heavily on
him. On the tenth anniversary of his and Carola's first meeting, as
well as his friend's death, Preston breaks down and tells her about
the monster. Carola appears uncomfortable by Preston's revelation and
then emits a heartbroken wail, saying he had promised never to tell
anyone, revealing herself as the creature that killed his friend.
With Preston's vow broken, Carola can no longer remain human and
begins transforming back into a gargoyle. Their children, now awake,
are terrified as Carola writhes in pain as hideous-looking arms and
legs burst from beneath her human flesh. A terrified Preston pleads
for Carola to change back, but she cannot assume a human form again as
her transformation back into a gargoyle keeps on continuing. Their
children are screaming in their bedroom as they also transform into
gargoyles. Carola, now fully transformed back into a gargoyle, wraps
her wings around Preston and the couple proclaim their love for each
other, but with the vow broken, Carola is still reluctantly forced to
kill him by biting his neck, before remorsefully flying away with her
gargoyle children. The final scene shows the three gargoyles now
turned to stone and sitting upon the building ledge, staring down at
the city with sorrowful expressions.