Passively gives flight whether it has charges or not.
If Isaac's speed is less than 1.5, passively increases his speed to 1.5.
Upon use, Isaac charges in the direction the pony is facing, giving invincibility during the charge and dealing contact damage to enemies.
The dash deals 40 flat contact damage to enemies.
Invincibility granted by dashing will not prevent Isaac from being damaged by Blood Donation Machines, Devil Beggars, and similar self-damage active items (when holding Schoolbag).
The dash deals 4 times Isaac's damage, plus a flat 28 damage.
Isaac can dash through doors, which means that damage from Curse Room doors can be avoided.
The dash persists through rooms, and lasts up to the length of 2 normal rooms unless Isaac collides with a closed door/wall.
This allows Isaac to enter and exit curse rooms for free, provided the dash is activated to give invincibility before charging through the exit.
Caution should be taken when dashing into rooms that have not been explored, as some room layouts have Blood Donation Machines or Devil Beggars, which Isaac may dash into and get damaged.
The flight and potential speed added by A Pony will be removed if a new activated item is collected.
If Void is used, Isaac will not be granted permanent flight.
Synergies
Book of Virtues: Spawns wisps in the middle ring, looking like "A Pony". The wisps charge in the direction Isaac shoots instead of firing tears. While charging, the wisps deal contact damage equal to 40% of Isaac's damage per tick (120% of Isaac's damage per second) and are immune to damage. Wisps must wait 2.5 seconds after hitting a wall before they can charge again. The wisps deal their normal contact damage while not charging.
Mars: Lowers the dash cooldown to approximately 1 second.
Taurus / Thunder Thighs: The speed decreases from the items can lower Isaac's speed past 1.50 (making the new lower speed limits 1.20 and 1.10, respectively). Having both items can lower the minimum speed to 0.80.
The dash deals 40 flat contact damage to enemies.
Blood Donation Machines, 
Devil Beggars, and similar self-damage active items (when holding 
Schoolbag).
The dash deals 4 times Isaac's damage, plus a flat 28 damage.
Curse Room doors can be avoided.
The Lost and 
Tainted Lost, as 
Holy Mantle or 
Holy Card can not prevent damage from them.
Headless Horseman, as a starting item for 
Eden, by using 
Spindown Dice on 
Bomb Bag, or by using 
Death Certificate.
Void is used, Isaac will not be granted permanent flight.
Book of Virtues: Spawns wisps in the middle ring, looking like "A Pony". The wisps charge in the direction Isaac shoots instead of firing tears. While charging, the wisps deal contact damage equal to 40% of Isaac's damage per tick (120% of Isaac's damage per second) and are immune to damage. Wisps must wait 2.5 seconds after hitting a wall before they can charge again. The wisps deal their normal contact damage while not charging.
Mars: Lowers the dash cooldown to approximately 1 second.
Car Battery: No effect.
Taurus / 
Thunder Thighs: The speed decreases from the items can lower Isaac's speed past 1.50 (making the new lower speed limits 1.20 and 1.10, respectively). Having both items can lower the minimum speed to 0.80.
Mom Unlocks 
The Binding of Isaac: Rebirth
