Elizabeth Lail Dead of Summer Freeform

The things you learn at summer camp will follow you forever, and on Tuesday’s (Aug. 23) penultimate episode of “Dead of Summer,” our campers learned that it’s always the quiet ones you should keep your eye on.

We’ve had our suspicions that Amy (Elizabeth Lail) wasn’t exactly the sweet ball of sunshine she pretends to be for a while now, but we figured that was all due to the fact that a demon was possessing her and trying to steal her soul. As it turns out, she’s just straight up evil — demon or no demon.

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After exorcising Malphas from Amy, her fellow counselors figured she was free and clear. Boy, were they wrong.

Flashbacks to her tortured childhood show that she poisoned her whole family after her brother locked her in the garage. And that little accident with her friend on the roof? Totally not an accident.

Even more troubling, Amy has been murdering people all over camp — dressing in black robes and horrifying satanic masks, to boot. She even offs Deb (Elizabeth Mitchell) with an axe.

Naturally, fans were just as stumped as we were to find out that Amy is a little bit psycho.

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We suppose there were always clues, like the gardener who told her she didn’t belong at Camp Stillwater … who quickly turned up dead. Plus, we probably should have been more suspicious that the demon chose her out of all the possible youngsters at camp.

As we move into the finale episode, does this mean that “Dead of Summer’s” last episode will just be a straight up summer camp slasher flick, with an axe-wielding Amy chasing everyone around Lake Stillwater? Because we’d be kind of into that.

The “Dead of Summer” season finale airs Tuesday, Aug. 30, at 9 p.m. ET/PT on Freeform.