Phlogistonic Conundrum

Phlogistonic Conundrum comes into play tapped.
{t}: A target player adds {r}.
{2},{t}, Sacrifice Phlogistonic Conundrum: Each
player chooses a card name. Then each player
reveals the top card of their library. If the card a
player revealed has the name they chose, that
player puts it into their hand. If you did not put
a card into your hand, create a Clue token.
What substance is the power of divine change?