Ukanos, the Ever Rising Tide

Flash (You may cast this spell any time you could
cast an instant.)
Whenever you cast Ukanos or another spell with
flash, if it was cast from your hand, draw X cards,
where X is that spell's mana value, then discard
that many cards. If it wasn't cast from your hand,
tap target nonland permanent with lesser mana
value than this spell. It doesn't untap during its
controller's next untap step.