Rooftop Assassin

Flash, Rooftop Assassin can only be blocked by
creatures with flying.
In addition to Rooftop Assassin's casting cost you
may return a creature you own to your hand.
When Rooftop Assassin enters the battlefield you
may tap or untap target permanent. If you
returned a creature to your hand, Rooftop
Assassin enters the battlefield with two +1/+1 counters on it.