Syphon Caster

Play with the top card of your library revealed.
{t}: Syphon Caster deals 1 damage to any target,
and 1 damage to you.
{t}: Exile the top card of your library. If that card
is an instant or sorcery, Syphon Caster deals
damage equal to the number of colored mana
symbols in the exiled card's mana cost to any
target. Play this ability as a sorcery.