Enchant non-Wall creature you control
When Krovikan Plague enters, draw a card at the beginning of the next turn's upkeep.
Tap enchanted creature: Krovikan Plague deals 1 damage to any target. Put a -0/-1 counter on enchanted creature. Activate only if enchanted creature is untapped.
The Aura will be put into the graveyard if you lose control of the creature or if it somehow becomes a Wall.