The monster in Scary Shawarma Kiosk: The Anomaly appears to be the game’s penalty creature, and it grows behind the fridge/at the back of the kiosk when you make mistakes or fail to handle anomalies correctly.

What it is

  • The game description frames the night shift as being full of monsters pretending to be people, so the creature is part of the horror setup rather than a separate storyline character.
  • One guide specifically says that failing to catch anomalies results in a “6-foot mushroom creature” slowly growing from the floor behind you.
  • Another guide says repeated service mistakes make the monster next to the fridge grow, and too many errors can trigger the Neutralized ending.

Where it “comes from”

  • Based on the available guides, it doesn’t seem to come from a normal customer or a scripted human origin.
  • It behaves more like a manifesting anomaly punishment : the game spawns it or lets it develop when you miss checks, serve the wrong person, or ignore suspicious behavior.

Practical read

  • If you’re asking in plain terms, the safest answer is: the monster is spawned by the game as a consequence of mistakes , not introduced as a lore-heavy creature with a clear backstory.
  • So “where did it come from?” = from the game’s anomaly system, not from a specific in-story event that these guides identify.

TL;DR

The monster seems to grow from the floor behind the kiosk when you fail anomaly checks or make too many errors , and the sources I found do not give it a deeper origin story.