As new recipes are unlocked, a toast is shown cycling through all the newly unlocked items. As the amount of unlocked items grows, the cycle speed increases. Due to how floating-point arithmetic works, the division behind the scenes can end up using a zero which will end up throwing an ArithmeticException leading to a crash.

To exploit this, an attacker has to have privileges to use the /recipe command. And can do it by repeatedly executing /recipe take victim * followed by /recipe give victim *.