This addon allows players to add 6 different abilities to vanilla horses- Frost Walker, Super Jump, Speed Boost, Elytra Wings, the ability to carry an additional chest, or a totem of undying!

Creator: Da_4Th_Edge

How to use:

1. First get a tamed horse and put a saddle on it (as usual).
2. Placing specific blocks/items in the horse armor slot will activate certain powers. Removing them will deactivate the powers.
Frost Walker: Place a 'Packed Ice' to horse armor slot. Now your horse can walk over water!
Super jump: Place a 'Slime Block' to horse armor slot. Now your horse can jump very high and won't take fall damage!
Speed Boost: Place a 'Block of Redstone' to horse armor slot. Now your horse can run faster than ever!
Elytra wings: Place an 'Elytra' to horse armor slot. Now hold the 'Jump' button to fly up, release it to fly down!
Additional chest: Place a 'Chest' to horse armor slot. This will add additional 15 inventory slots to your horse.
**Removing the chest will make those additional 15 slots inaccessible, but your items won't be disappeared. To regain access simply place the chest back into the horse armor slot. You can utilize this behavior as a secret locker!**
Totem: Place a 'Totem of undying' to horse armor slot. Totem will save your horse from accidental deaths and disappear from the slot after a single-use, similar to how it behaves for players.

Limitation:

Right now this addon globally resets the randomized power jump values of all the horses to a fixed value. So be sure to take a backup of your survival world before activating this addon.