'M3GAN' ending explainer: What's the deal with that final shot?

Her fashion sense and wit are as sharp as her sense of justice. She's a toy that doesn't play around. Watch out for M3GAN. 

The freshly minted horror icon is in theaters, dancing and dooming any mortal who dares cross her. Specifically, her devotion to grieving orphan Cady (Violet McGraw) pitches the deranged doll in direct...