You can Tribute Summon this card in Attack Position by Tributing 1 Zombie-Type monster. When this card destroys a Zombie-Type monster by battle and sends it to the Graveyard, you can Special Summon that monster to your side of the field.
All monsters on the field and in every Graveyard become Zombie-Type monsters. Neither player can Tribute Summon monsters, except Zombie-Type monsters.
One of the most crackhead combos in old TCG. Maybe current, IDK, but I don't play much anymore.