Lanky: Of course a human would have to kill one of us to obtain one!
When a Enderman in born it’s pearl is connected to it’s own little hole in space which over time has become a chest. In it we can store our personal belongings, but only those that truly matter.
We can reach into it at anytime.
A human doesn’t have this therefore to obtain such a thing they need to take our pearl and then they will have access to that Endermans personal space or “Pocket dimension”.