jinks, jinx

Jinks or jinks, most commonly used in the expression "high jinks",  means pranks or antics; horseplay--
The principal was not amused by their high jinks.
No high jinks while driving, understand?

Jinx or jinx ( rhymes with jinks )  means a person or thing that brings bad luck or ruins plans--
Don't let him near the fire; he's a jinx.
Jinx may also mean to bring bad luck or to ruin plans--
Don't tell, you'll jinx it.

Now that you know that, you can say--
"The students planned the high jinks in order to remove a jinx, one that supposedly caused bad grades."

Note--"Jinx" is also a girl's given name--
"Hi, Jinx!"