Doppelganger

Doppelganger by Brandon Scott (a Short Story Contest entry) 

The boy heard his parents with them downstairs. Laughing. Schmoozing. While he lay in darkness, facing the open closet.

Silently a shadow emerged, twisting on all fours. Like a bug. It looked like him. But smelled like mud.

“Stay quiet,” it said with his voice. “I’m trying to help you—"

Suddenly, choked screams erupted from the people below. Groaning in pain, the voices warped.

“Oh no,” it said, afraid. “They’re changing already.”