You canâ€™t cast a spell without choosing legal targets. If all of those targets become illegal, the spell doesnâ€™t resolve and you wonâ€™t investigate.
The tokens are normal artifacts. For example, they can be sacrificed to cast Angelic Purge or targeted by Root Out.
The token is named Clue and has the artifact subtype Clue. Clue isnâ€™t a creature type.
If you sacrifice a Clue for another cardâ€™s cost or effect, such as that of Angelic Purge or Tamiyoâ€™s Journal, you canâ€™t also pay and sacrifice it to draw a card.