Small Lockbox

"And what's this? A cute little box! I wonder what's inside… Ouch! It burns! This box must be cursed! Some kind of anti-theft measure? Let's get it to the Ministry. They'll need to break the curse if we want to find out what's inside!"

- Mathilda Grimblehawk and her partner stumble across this lockbox in the Secret Owlery, during the course of the Ministry investigation on Bilius Finbok's disappearance

This Small Lockbox was used by Bilius Finbok to store a handful of frozen Ashwinder eggs and a a receipt from Slug & Jiggers Apothecary, and was kept in a Secret Owlery in the middle of Muggle farmland in Cornwall. It contained a curse that burned the hands of whoever tried to open it.

It was discovered by Ministry of Magic investigators Mathilda Grimblehawk and her partner during the course of the investigation of Bilius Finbok's disappearance. They found out the box was cursed when Mathilda tried to open it, and sent it to the Ministry for experts to lift the curse; according to Cerberus Langarm, the "poor curse-breaker had to have a lie down after this one".