Investigate, then target creature gets +1/+1 until end of turn for each Clue you control. (To investigate, create a colorless Clue artifact token with ", Sacrifice this artifact: Draw a card.")
4/8/2016 No player may take any action in between the two steps of Confront the Unknown, so the target creature will get at least +1/+1.
4/8/2016 The token is named Clue and has the artifact subtype Clue. Clue isn’t a creature type.
4/8/2016 The tokens are normal artifacts. For example, they can be sacrificed to cast Angelic Purge or targeted by Root Out.
4/8/2016 If you sacrifice a Clue for another card’s cost or effect, such as that of Angelic Purge or Tamiyo’s Journal, you can’t also pay and sacrifice it to draw a card.
4/8/2016 You can’t cast a spell without choosing legal targets. If all of those targets become illegal, the spell doesn’t resolve and you won’t investigate.