The Drowned, Abiss Walker

Indestructible, Flash

When The Drowned, Abiss Walker enters the battlefield you gain control of all other opponent's lands until your next turn unless every opponent pays seven lifes.

All of your creatures gain Wither (whenever a source with wither deals damage to a creature, that creature receives a number of −1/−1 counters equal to the damage dealt to it)
All the spells in your graveyard have a Retrace cost equal to their mana cost less {2}