Thief of Souls

Flash, Dual Haste (this creature may attack in the
turn it entered on the battlefield, if it's not your turn
you may declare this creature as an attacker at the end
phase, it can only attack in your oponnents turn in the
turn it entered the battlefield)
Whenever a creature you control attacks in an
oponnents turn he loses 2 life and you gain 2 life
it appears from nowhere, and takes every drop of hope