Cosmen, The Explorer

Flying
Whenever you draw your second card each turn,
you may reveal it. If you do, reveal the top card
of your library, if it has a lower converted mana
cost than the card you revealed, draw it. Repeat
this ability until you draw a card with a greater
mana cost than the one before it.
"Of all the explores of Ixalan none come close
to Cosmen"