Dubious Spellcaster

{u}{u}{t}: Counter target spell. It's controller
draws 2 cards. Sacrifice Dubious Spellcaster.
{4}{u}{u}: Force an opponent to cast a spell of your choice from your hand (give the card to that opponent, he or she is the owner of the card until
the end of the game). You pick which of that
opponent's mana sources are used to cast the
spell. Mana of any color may be used to cast it.
"Here, take this."