DM: When you look at it, you see an ordinary stick, nothing more...

Player: What do you mean a stick?

DM: It is a stick.

Player: (Sits in silence rethinking his life choices).

Whenever a player picks up "A stick", they must make a DC 19 wisdom saving throw or suddenly be effected by the confusion spell for 1 minute, on success they aren't effected by the spell and instead feel an odd urge to point it at something.

Player: (Points it at his party's dwarven cleric).

DM: Suddenly Bob the cleric explodes in flames after you happen to point it at him

Player: What?! Did you just kill off Bob?

DM: ...

When pointed at something with the intent of "A stick" doing something, "A stick" casts fire ball as a 5th level spell.