Veigar, Tiny Master of Evil

Whenever you cast an instant or sorcery spell,
you may sacrifice another creature with the same converted mana cost as that spell.
If you do, copy it. You may choose new targets
for the copy.
When Veigar enters the battlefield, you may sacrifice another creature.
If you do, you may cast an instant or sorcery with
the same converted mana cost as the sacrificed creature.