Let's say we use this idea, we can't find any good "end" to the movie. Like, what happens when the student realizes it's the janitor? Take a cop coffee or something with him lol? We are thinking of something funny.
My actors are all a bunch of screwups so I have to come up with stuff myself, and that isn't always easy, so I need your help to come up with a funny end to the movie.
Lots of funny ways you can end it! Thinking about it a bit more, I'd probably end it:
-sees the janitor
-sees the calendar
-reaction shot of him realizing his mistake and feeling like an idiot
-cue credits and overblown, jarringly silly music
You could also twist it again:
-sees janitor
-sees calendar
-feels like an idiot
-janitor changes the date on the calendar...it actually IS a school day and he actually IS a monster
-scream, fade to black, credits
That'd give you some VFX stuff you could do (transforming the janitor into a monster)
Take that twist and, twist again:
-as before, monster, scream
-wake up in the classroom...he has fallen asleep in class
-looks around, students and teacher are all monsters/zombies and staring at him
That'd be funny if you play it not with a "we're about to eat you" but a "how could you fall asleep in my class" expression on the teacher.
You could play it completely random; you mentioned wanting to do something with guns, have the janitor pull a gun on him and start shooting, and he pulls a gun in response. If you were doing that, I wouldn't resolve it, but have it fade in the middle of the gunfight. Let the audience decide who wins!
Thinking of the absurd and random, I could almost see that turning into Monty Python-esq animation!
Of course, my taste in funny is a little bit odd!