Accursed Witch

Creature — Human Shaman4/2
Spells your opponents cast that target this creature cost

less to cast.
When this creature dies, return it to the battlefield transformed under your control attached to target opponent.
Infectious Curse
Enchantment — Aura Curse
Enchant player
Spells you cast that target enchanted player cost

less to cast.
At the beginning of enchanted player's upkeep, that player loses 1 life and you gain 1 life.