Wikipedia: "A doppelgänger is a tangible double of a living person in fiction, folklore, and popular culture that typically represents evil."
Fiend Folio: "The CIFAL--the name is acronymic of 'colonial insect-formed artificial life'--is an agglomeration of several swarms of insects...which come together to form a single amorphous creature about man-sized.
Wikipedia again: "Aggressive mimicry is a form of mimicry where predators, parasites or parasitoids share similar signals with a harmless model, allowing them to avoid being correctly identified by their prey or host."
I feel like you can probably figure it out from there, right folks? We're all DMs here. She's not your auntie, she's bugs. The first hint is usually subtle, a fly emerging from the left nostril as someone lights a cigarette, etc.