Ongoing Investigation

Oracle Text

Whenever one or more creatures you control deal combat damage to a player, investigate. (Create a colorless Clue artifact token with "2, Sacrifice this artifact: Draw a card.")

1G, Exile a creature card from your graveyard: Investigate. You gain 2 life.

Card Rulings

4/8/2016 In a Two-Headed Giant game, if you control more than one creature that can attack, you may have them attack different opponents so that Ongoing Investigation’s first ability triggers twice.
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.