Sabine Wren, Explosives Expert

Vigilance, First Strike
When this creature enters the battlefield, destroy
up to two target creatures your opponent controls.
Draw a card for each creature destroyed this way.
When this creature deals combat damage to a
player you may pay {x}. If you do deal X damage
to target player, where X is the cost paid to
activate this ability.
{2}{r}{r}: Put three +1/+0 counters on target
creature until end of turn.