Sacrificial Dagger

Sacrificial Dagger is an unlockable passive item.

Effect

 * Spawns a sideways dagger that orbits Isaac, deals high damage to enemies on contact, and blocks enemy shots.
 * The knife deals 15 damage every 1/15th of a second (every 4 frames) or 225 damage per second.
 * The knife deals 15 damage every 2/15ths of a second (every 8 frames) or 112.5 damage per second.
 * Hitbox size reduced.

Trivia

 * In the original Binding of Isaac, Sacrificial Dagger rotated upright, while in Rebirth it now orbits on its side.
 * This item is used in Challenge #4 (Darkness Falls).
 * While the in-game name and Steam achievement name says 'Sacrificial Dagger', when unlocked, the in-game text shows 'Sacrificial Knife'.
 * The Sacrificial Dagger's description is likely a reference to the Jewish story of Abraham's sacrifice of his son, Isaac (in what is known as, literally, the Binding of Isaac). Abraham took his son Isaac to a mountain to sacrifice his son at the command of God. Despite being commanded to do so, he knew through his faith that God would not allow his son to be sacrificed.

Seeds
99KW 09AC (treasure room adjacent to spawn) O98E HJO7 (treasure room adjacent to spawn) F4WJ R3DD (First Golden Treasure Room)