It's one of the stress gauges, the unnatural. The floating girl causing you to question what is normal and what isn't.
Make a roll, you're trying to get under your Mind skill. Success gives you a hardened notch in the Unnatural and brings you closer to no longer having any reference point as to what is "normal" and what isn't.
Failure gives you a failed notch and brings you closer to absolute mental breakdown. Plus, in the short term, you must decide between the fight, freeze and flee reactions. Gimme a sec and I'll dig up the post where I talk about them in more depth.