The Leech

Soulbind to Target Opponent (When The Leech enters the battlefield, choose an opponent's creature. That creature is now your “host.”)

Drain Presence :At the beginning of your host’s upkeep, The Leech deals 1 damage to them and you gain 1 life.

Unrelenting Commentary :Whenever your host casts a spell you may copy that spell. You may choose new targets for the copy.
Overstay Welcome — Your host’s spells cost 1 more to cast for each turn The Leech has been on the battlefield.