When the 3rd graders go to the principals house and he's wearing the revolting blob mask, his door is open so look into his house. Down the hall you can see someones shadow in his house for a very brief second its not right when he opens the door, but it is in this scene. Its very brief, so look hard.
well maybe there was someone in his house! like maybe a "friend" everything in movies cant be perfect i mean they are real people just like everyone else everyone makes mistakes
If someone was at his house, why was he wearing the mask? I was under the impression that he tried to keep his past a secret. I have a hard time believing that the shadow was supposed to be there...however minor, it was definitely a slip!
The inside joke is that Max Anderson was gay (as per the Valentine scene). That joke was the premise for the Revolting Blob costume and the "second" person. It was a sexual innuendo that Tim Herlihy and Adam Sandler put in the script as a joke. Josh Mostel (Max) is really gay.