A Unicorn's horn, severed from its head.
Upon activation, Isaac will start flashing in different colors and a special tune will overtake the background music for the duration of the effect. Isaac will be immune to all forms of attack and can only attack by touching his enemies. This effect will last only for a few seconds, and Isaac will blink rapidly before the invincibility is gone. While under this effect, Isaac's Speed is increased by 0.28.
- Blood Bank - Isaac can use My Little Unicorn and use the blood bank multiple times without losing health for as long as the invincibility lasts. In Wrath of the Lamb, this will also work with Devil Beggars, Sacrifice Room and Curse Room (one-way only, as effect stops on changing rooms)
- Mom's Knife - You won't be able to throw the knife, but you will cause extreme damage on contact (due to Mom's Knife's damage and My Little Unicorn's damage mixing together).
- Technology 2 - You will be able to fire, but the laser will be invisible.
- The effect of this item is identical to that of the VII The Chariot tarot card.
- Although you cannot shoot tears for the duration of the effect, Familiars can still shoot tears.
- The name of this item is a reference to My Little Pony , a franchise of pony toys that has spawned several cartoon adaptations.
- The effect of this item is a reference to the Star powerup for the Super Mario series. Getting a Star will cause similar effects, including: invulnerability, flashing colors, change of music, an increased speed, and a damaging touch.
- It could be a reference to the game "Robot Unicorn Attack" which features psychadelic visuals and an endlessly charging invincible protagonist.
- In vanilla Isaac, the invincibility would not protect you from Mom's hand.
- If My Little Unicorn is activated before beating the Chest, the item's tune will continue into the ending cutscene.
- My Little Unicorn, like all other contact damage items, cannot inflict contact damage to Hearts or Mom's Heart/It Lives, but can do so to other enemies that don't deal contact damage to the player.
- Using the My Little Unicorn in the Isaac fight will allow the player to exit the room via closed door, efficiently resetting the boss.