License to drill
A License to Drill is an Activatable Artifact.
Activating this artifact will make your hero search for allies to fight an underground boss.
This works even if your hero's still on cool-down from his last dig boss. Consumes 50% GP.
Note: This does not guarantee that your hero will actually get an underground boss to fight - if your hero fails to find any allies, he will just continue with what he had been doing before activation.