Vaaliizstrun, Ice Wyrm

Flying, Ward {x}, where X is the total mana of the
last instant or sorcery you cast.
As an additional cost to cast this spell, pay 5 {s}. Otherwise, Vaaliizstrun, Ice Wyrm gets sacrificed at the beginning of the next end step.
When you cast or copy your next instant or
sorcery, you may pay {r}{r}. If you do, copy that
spell. You may choose new targets for the copy.