One last thought as April Fools leaves: if you're a teacher, you should never pull a prank that has multiple people panicking about an uncorrectable zero.
I mean, frankly, if you're in a position of power, you shouldn't pull pranks, but especially not ones that abuse the power you hold.
I mean, I guess one funny one might be coming into class and teaching the wrong thing, e.g. teaching freshmen senior-level stuff and vice versa. That might be amusing, if only to see how long it takes someone to go "What the fuck is this shit?" But, Iean, you'd still have to be careful with that.