Gareth Dane, Arena Brawler

Whenever you pay life, you may destroy target creature with power less than or equal to the
amount of life you paid.
Pay X life: Reveal the top card of your library.
You gain life equal to that card's converted mana
cost. If that card's converted mana cost is X or
less, you may put it into your hand. Otherwise,
put it into your graveyard. X can't be less than 1.