Cave Investigation

Whenever one or more creatures attack you or a planeswalker you control, investigate. (Create a colorless Clue artifact token with ''{2}, Sacrifice this artifact: Draw a card.'')
As long as you've completed a dungeon, abilities
of Clues you control cost {1} less to activate.
''This cave doesn't feel very safe. I think I've seen something move in the dark. I'll mind my steps.''