Looking closely at the photo, it looks like the pin at the top has been sheared off and might be part of the key that got stuck in the lock.

Yup something a bit like this! Don't know how they're called though...
Maybe in an antiques shop?
Looks designed to make it harder to pick by not letting you get tools in there easily.
There are keys with hollow ends/barrels. It looks like that could be the case.
I have seen this type of key on older furniture, but they usually have the "archetypal" key hole shape. This one seems to have some added security and looks like one of those warded keys. I have yet to find warded keys of this shape with a hollow tip
It's a pop top.
soda can
What is this thing?
Let us help you identify that mysterious object you’ve found.
Currently in CHALLENGE mode: If you've got something obscure knocking about, post a picture, and let's see how we do. Please prefix such posts with "CHALLENGE:" so we know we've got a fighting chance.