↓ Transcript
[Andy turns toward the window as her classmate points at something.]

Classmate: What is THAT?

[A shot over Andy's shoulder; the apparition at the window is gone.]

[Andy gives her a look; her classmate shrugs and grins as the bell rings.]

Andy: That would be the lawn.
Classmate: I must be seeing things! Ha ha...

SFX: RIIIIIIINNNNNNGGGGGGG