Spawns a red wisp when Isaac takes damage that fires spectral tears and deal contact damage to enemies (but does not block projectiles). These red wisps last for the entire floor, and Isaac can have up to 6 red wisps at a time.
Wisps deal 3 + 0.1 * (current_floor - 1) damage per tear, and fire tears once per second.
Wisps deal contact damage equal to 0.5x Isaacs's damage per tick (15 ticks per second = 7.5x Isaac's damage).
The wisps share the first layer of Book of Virtues wisps so combined with them, you can't have more than 8.
BFFS!: Doubles the wisps' size, on-hit and contact damage.