Plague Boiler
{3}
Artifact
At the beginning of your upkeep, put a plague counter on ~this~.
{1}{B}{G}: Put a plague counter on ~this~ or remove a plague counter from it.
When ~this~ has three or more plague counters on it, sacrifice it. If you do, destroy all nonland permanents.
Traveling Plague
{3}{B}{B}
Enchantment -- Aura
Enchant creature
At the beginning of each upkeep, put a plague counter on ~this~.
Enchanted creature gets -1/-1 for each plague counter on ~this~.
When enchanted creature leaves the battlefield, that creature's controller returns ~this~ from its owner's graveyard to the battlefield.
Withering Hex
{B}
Enchantment -- Aura
Enchant creature
Whenever a player cycles a card, put a plague counter on ~this~.
Enchanted creature gets -1/-1 for each plague counter on ~this~.