Mr Mehr, Master of Instruction

{w}{u}{u}, {t}, Exert Mr Mehr, Master of Instruction: Target creature you control gains all abilities of Mr Mehr, Master of Instruction.
Mr Mehr, Master of Instruction's power is equal to the number of cards in your hand.
{u}, {t}: Differentiate target equation. (Scry 3)
{w}, {ut}: Integrate target equation. (Draw a card)