Artifacts are often an objective of missions. In some missions, you simply have to retrieve the artifacts. In others, you must protect them. In missions where you must protect artifacts, after attacking enemies that surround them, several more groups will approach to try to destroy the artifacts. In order to successfully protect the artifacts, a hero must defeat all of these groups. You will usually be told via a system message in your chat window when you have successfully defended an artifact.
This case holds an ususual item.