A white feather, presumably from a dove.
Upon activation, beams of light will appear in random locations on the ground. Each beam will last for 0.8 seconds and will deal severe damage to any enemy that touches the light beam.
- Crack The Sky is too random to selectively take out singular enemies. However, it can be used to quickly reduce the number of monsters in a crowded room (Challenge Rooms in particular) if it hits, and is also very effective against larger bosses like Gurdy
- Will hit off-screen enemies, but won't damage a downed Host.
- The unlockable Horseman Conquest uses this Item instead of the Troll Bombs, whereas War uses the Tower Effect.
- His regular drop White Pony also has the Crack The Sky effect.
- Similar to the The Candle, this item can damage Mom's Heart/It Lives while the boss retreats and can damage Satan as well by targeting the statue before finishing the battle against The Fallen.
- The item is a reference to the 2009 Mastodon album "Crack the Skye"
- Which in turn is likely to be a reference to a line in Shakespeare's King Lear where the eponymous king rants at the gods to strike him down in a thunderstorm.
- The crack the Skye album's was written partially in homage to the bands drummer Brann Dailors sister named Skye who committed suicide at 14 , referencing Isaac sister shown in ending 13 and the Sister Maggy item