Black Lotus

Black Lotus is a passive item.

Effect

 * Grants a full red heart container, a soul heart, and a black heart.

Seeds
4YG3 TX2Y (First floor secret room. Secret room is located two rooms left and one down from the start. Item room contains Dr. Fetus for easier access.) 0JGY 6ZWX (First floor secret room next to treasure room) HW7N ZCXL (First floor secret room left of curse room) E0LA 1C4E (First floor secret room next to treasure room) NVLY 9BRN (Secret room to the left of spawn) BTL9 9SAE (Secret room below spawn) 8F7C VWCX (First floor secret room, just below the spawn) YY8V P4HM (Second floor secret room left of the curse room. Keep pill from first floor to make it easier to find)

Trivia

 * This is a reference to the iconic card of the same name from Magic: the Gathering, a collectible card game Edmund McMillen played since his childhood.
 * Its powerful effect of producing three Mana of any color is reflected by the ingame item's effect of adding three hearts of different colors to the player's health.
 * The fact that it's one of the rarest and most expensive commercially released cards in the game might also be referenced by the fact that it's a relatively hard item to come across, being only a rare find exclusively in secret rooms.