enchant player
as this permanent transforms into curse of leeches, attach it to a player.
at the beginning of enchanted player's upkeep, they lose 1 life and you gain 1 life.
daybound (if a player casts no spells during their own turn, it becomes night next turn.)
//
leeching lurker
enchantment — aura curse (4/4)
lifelink
nightbound (if a player casts at least two spells during their own turn, it becomes day next turn.)
First darkness falls. Then it burrows in.