Oma, God of Knowledge

This spell costs {1} less to cast for each card
you've drawn this turn.
Whenever Oma enters the battlefield or attacks,
draw a card. Each opponent loses 1 life for each
card you've drawn this turn, then you gain life
equal to the life lost this way.
Whenever Oma dies, return it to its owner's
hand at the beginning of the next end step.