locker

A:  I can't open my locker, and I need your help bro.

B:  Why? What happened?

A:  The key is locked inside.

B:  How could it happen?

A:  I am silly....

B:  Anything else inside?

A:  No, not really.

B:  Then just get a new locker. Be careful about it.

A:  I can't ... because my body is the locker.

B:  Oh...Now I see what's the key is...